Actually the nature of dead ends really changed in KQ5 (though some might argue KQ4 for certain reasons). That game had alot of unique deaths that were only triggerable if you made wrong decisions. For example being killed in the woods by spiders, man eating plants, and or becoming lost! Didn't have all the stuff for the inn? Well that lead to a timed death!
I think it was also largely the first game to throw out warnings ahead of time for areas that might require more items (predating the catacombs warning).
KQ6 had a few puzzles were you could get stuck without the proper items much like the original KQ games. For example forgetting to get the mechanical nightingale before going into the castle on the short path! or if you forgot to talk to the mother ghost! Or forgot the skeleton key! There is at least two possible ways to get yourself stuck from even being able to enter the castle! With no way to die and just wander forever! Accidentally break the egg after burning the dress, or forgetting the Styx water!
Regardless, my overall point remains the same. There's trying to refine a concept and then there's changing the concept completely. Adventure games seemed to stray too far from what their very nature was and I think that's what put the final nail in the coffin.
This largely depends on the company, many companies didn't follow the Infocom and Sierra approach to adventure games. Quite a few companies such as Lucasarts had adventure games with few ways to die, and no intentional dead ends. It's safe to say each company defined their own views of what adventure games were early on, and rarely strayed from their own formats.
On an interesting side note, I learned that KQ7's single icon interface was apparently inspired by the streamlined menu system in Westwood studio's Legend of Kyrandia series. Again I'd agree that was a change for the worse!
And then after KQ7, it's as if they noticed the popularity of shooters, so they made Mask of Eternity and tried to act like it was still an adventure game. Absolutely not! Overcoming obstacles, trading with characters, and using your wits to travel and explore a new land to find a key to a magic door is an adventure game. Jumping on tiles in a given order so that you can be given a key to open a door to kill skeletons is not an "adventure game puzzle." They further altered what an adventure game was. Or rather, they just made a first person shooter and called it an adventure game.
There is very little in KQ8 that can be called a first person shooter. If anyone calls it that they are showing the lack of knowledge of the game or understanding! Either that or using extreme hyperbole. Perhaps even going so far to be intentionally misleading!
The game is a hybrid game. If anything its bit more action-adventure genre (tomb raider), hack and slash genre (the combat focuses on swords not projectile weapons), and while you can use a single projectile weapon at a time, many of the enemies are immune to projectiles (so the hacking and the slashing is the weapon of choice). The combat style is point and click mouse clicking which takes from assorted RPG genres like Diablo series. It's also a bit like Quest for Glory in some ways (although alot more streamlined and simplified mechanics). On top of that it maintained the inventory puzzle interface of the previous KQ and other Sierra games, and the streamlined single cursor interface of KQ7. In many ways it has more in common with the 3-d Zelda action-adventure series, and no one claims OOT is a FPS.
Additonally while you can play in first person, the game actually controls better in 3rd person in most places. You also get some special attacks in third person you cannot access in first, certain jumping actions can only be made in the 3rd person. Also if you try to fight primarily in first person you probably will take alot more damage, as you can't really defend as well, or dodge attacks from multiple enemies. Plus the character changes appearance throughout the game, with new armor, and weapons graphics. These area only truly showed off in the 3rd person view mode. Jumping, backflips, etc is not indication of FPS genre (or any genre for that matter, except for maybe platformer, but KQ8 is not a platformer), and even KQ1 had jumping (although this has more in common with action-adventure games mentioned above)!
While I do admit that the addition of box, jumping and tile puzzles (the latter of actually are quite similar to the tile puzzle in KQ6) are a bit naff, they are aren't the sole type of puzzle in the game. The box puzzles are ripped out of Tomb Raider/Prince of Persia/Indiana Jones, even zelda style games, and even further back to early adventure games. On a side note, there is another 'adventure game' puzzle that many complain about in Adventure games, and that is the "maze' style puzzles, like Catacombs and the Labyrinth under Mordack's castle. Often cited as one of the top ten worst things in adventure game design! KQ8 had a couple of those types of areas as well...
BTW, its important to point out that block and tile-style puzzles are not traditionally puzzles one finds in First Person Shooters. FPS in general, especially the earliest ones, are not known for having puzzles, especially not those those two particular types of puzzles. With the exception of say Half-Life which took elements from Adventure game design in order to push itself outside of the mold of the standard FPS genre!
No, the box and tile puzzles are generally an aspect of adventure or action-adventure genres. Or part of their own genre if a mini-game ('boxxle'). You may not know this but block puzzles go back to Infocom adventure games, for example in Zork 3, in one of the 'mazes' in the game (yes the third dreaded adventure game puzzle design type) involved pushing walls around in certain order, to find the exit and secret items! Let's just say its maddening especially since you have to imagine what's going on! Tile-based puzzles appear in many adventure games as well (KQ6 and KQ8 are not alone), for example several of the early Indiana Jones adventures (last crusade, and Fate of Atlantis)! These are some of the most over used in adventure game puzzle design, and some of the earliest adventure puzzle types! Some of the later Zork games also had tile based puzzles/chess-style puzzles! Btw, look at Torrin's Passage for a tile jumping puzzles that are quite analogous to the KQ8 puzzles! Its in the lava world area. I'm hard pressed to think of any FPS that has tile puzzles (and box puzzles are something later FPS nicked from earlier adventure game genres).



As far as puzzles the game has more than most KQ games put together, it has more of the classic item/trade puzzles than KQ1, it adds additional physic based puzzles, some environmental puzzles. In several examples even weapons become traditional inventory style puzzles for influencing the environment! Cutting down a tree, freezing water, breaking locks, etc.
Remember that puzzle in KQ5 where you had to break a lock with a hammer? Well KQ8 has the same puzzle, just with a bigger hammer!
But ya, you point towards several of the puzzles in the game (definitely not all) can arguably described as 'fetch quests'. Quite a few puzzles in previous games were the same way. You were given an item, and then told how and where to use it by some character. This seemed to be worse in later games starting with KQ7. While not so bad in the first area the Desert (which can be tricky). Once out of the desert, much of the game devolves down to characters sending you on quests to find random items they need (fetch quests)! Or they tell you exactly what you need to get past certain obstacles, thus sending you out to find the item, so you can use it the way they explained it. Again not every puzzle, but many of them!
Although I'd say KQ3 is just as bad, as you are pretty much told which items to 'fetch' for the spells in the manual, and how/where (as in environment) those spells are literally used. So nearly every puzzle in the game is 'spelled out' in the manual completely. There are very few puzzles that manual does not cover. So all that's left is to search for everything mentioned in the manual, so the 'fetching' occurs. That actually was one reason the game received much criticism in reviews back in the day!
You know those 'find ingredients" for spells from KQ3 also appears in KQ6, in KQ7 and KQ8. These are essentially a type of fetch quest!
One of the earliest and well received adventure games, "Mixed-Up Mother Goose" and it's sequel Mixed-Up Fairy Tales are made up of nothing but 'fetch quests" of the most simple kind (the few fetch quests in KQ8 are much more complicated)! Fetch Quests are not specifically elements of FPS either (but something nicked from the Adventure game genre).
Really the only thing the game added, that can't be traced back to older adventure games was the RPG-style 'combat' and 'action'. Perhaps the physics-based and environmental-puzzles are also a new addition to the game (although there are a few random examples in other games out there). Although even still its not the first adventure game to have RPG or action elements, check out some other weird hybrids like Beyond Zork (RPG/text adventure) QFG (rpg/adventure/arcade), Inca series (flight/space combat sim/Adventure/shooter), and several of Dynamix's offerings (Heart of China and Rise of the Dragon). Physical based puzzles though rare do show up in occasional earlier game (just 3-d engine makes it more obvious).
I'd say one of the problems with the game was it tried to be everything to everyone! It might also be said, that one of its biggest flaws were most of the puzzles were based on too many overused and cliched adventure conventions from the graveyard of puzzle design! It simply wasn't original enough (which was a problem with many of the adventure games in the death period)!
http://www.postudios.com/blog/forum/index.php?topic=10923.0On a related note, did you not notice that at that time a very traditional adventure game, Grim Fandango, pretty much bombed in relation other games at the time (though well received by the niche adventure game community)? Even KQ8 outsold it twice as much (and was one of the best selling 'adventure' games that year). That right there, should give you indication that as far as the market was concerned, Adventure games were not particurarly successful. Most companies were more concerned with more profitable genres.