I know there is a huge number of changes in SQ1, but I thought I'd toss in some examples,

. It would be a bit difficult to liste all the changes from memory.
It really can't be called a 1:1 remake, and I never called it a 1:1 remake. Infact I think I said specifically that SQ1 remake is not a 1:1 remake.
I wouldn't call the KQ1 remake a 1:1 remake either. There were quite a few puzzle changes, redesign of Daventry's appearance, changes to the story, etc.
About the only Sierra remakes that remained 1:1 essentially, were the Mixed-Up Mother Goose, and possibly Leisure Suit Larry 1 (although it wasn't quite 1:1 either, it added a few extra things, and changed some of the dialogue) I don't know if there were any changes to the puzzles in LSL1 remake though.
I'm seriously a bit confused where this 1:1 remake terminology comes from even, because Sierra never claimed that their remakes were 1:1.
where most of KQ3's visuals were very close redraws (if not straight paint-overs) of the original AGI artwork.
Some of it ya. But the top of the mountain is different, two screens instead of 1. Southern and Northern edges of Llewdor are different (the original didn't have "edges"). They also changed a few locations of the items (and the names of the items). It also contains quite a bit of added diaologue over the original version, and descriptions in the screens.
Did you know that on the map in the original for example both the city and Three Bear's house are located south of the mountain. Yet you can see both the city and the bear's house to the north of the mountain. The game really plays with that continuas warping, and it literally does exist in the world. From the bear's house you are told that the mountain can be seen to the north.


Once you get to Daventry, its filled with quite a few changes. Its more based on KQ5 type areas mixed with KQ1 remake areas, than the original KQ3. Plus its own changes to the map. For example you don't head directly north to get to the castle, you make a few turns from gnome's house before you reach the castle.

Plus completly changing the function of the map, changing the intro, changing the ending (it no longer fits with KQ4). Changing the cutscene in the crystal ball. Changing the spell system, etc. Actually I have a more complete list of the changes between KQ3 remake and the original on the omnipedia (including differences between the two versions of the KQ3 remakes).
In comparison, as far as "counting the screens" both versions of SQ1 have about the same total, although the screens were completely different appearance in both versions. Although certain things got shifted around (for example that deadly hole in the cliffs/skeleton are on completely different screens in both versions). Overall, while extended, the intro and endings are more or less similar to the original. Roger gets his mop in both. Most of the puzzles remained about the same, although an extra puzzle solution or two were added (one puzzle slightly modified).