I'll have to go on the side of the people who like King's Quest 7. In fact, I've been meaning to play it again soon.
Is it the best King's Quest game? Not by any means. Does it have much continuity in comparison to the first six games? Not especially. Are there some damn annoying bits to deal with (looking at you, firecracker glitch)? Of coruse.
But it did try something new. It also made itself a more accessible game which, with more people getting into games on CD, meant more people trying out King's Quest and looking back through the series as a whole. I'd actually played King's Quest well before the release of 7, but had long "lost touch" with the series. KQ7 brought this back for me and without it, I wouldn't have come back to the series. It also had the appeal to the female audience by letting people control female characters.
Sure, it probably looks a bit janky now, and the voice clips don't sound as clear as they would on a game of today. But for the time, the graphics were beautiful, and even now, the soundtrack is spectacular. Maybe not on the same epic scale as King's Quest VI, but it had its own charm and there were some pieces I found particularly atmospheric. The music at Manor Tsepish in particular always brings chills to my spine and haunts me.
There were some really interesting locations to visit as well, and such a large variety, too. From being in a desert, to underneath a volcano - a beautiful woodland, and a land of the undead... So many different characters and personalities to interact with.
I can quite see why some people wouldn't approve of it as much. It's "lightened up" a well-established series with bright cartoony graphics and songs. Gone are the humorous death sequences, and numerous references to fairy tale lore. But I still don't think it's a bad game. There have certainly been worse games with the "King's Quest" moniker on. There's still a lot going for King's Quest 7 and I don't think it should be dismissed just because it's moved slightly away from the norm.