I think the main problem with the escape section(s) (could be more, I have only done one) is that it changes how the game handles difficulty. The entire game works in that way where you never feel it's your own fault for messing up. You're always in control, you always have options, and you can always save to minimize frustration.
The water sequence is the first time I felt the game was unfair. It started to mess with it's own rules and it almost felt like a different game - in a bad way. It soured me a bit on the game, because now I'm dreading having to go through at least two more of these terrible sequences. I think a good solution would be to allow for one save half-way through the sequence.
I don't really care if I come off as someone who is easlily frustrated or doesn't like a challenge, because the game was plently challening leading up to this. It's really frustrating since I was thinking this is one of the top 10 best games I have played in MY LIFE before that sequence.
I felt the same way. Also the game cheats as you cant actually outrun the water, it will "rubber band" to you making picking up the xp orbs a huge pain. Awful sequence, the second is just as bad, I havent seen the third. I hated it and like you, it soured the game for me (then after that you forget it and love it again...until the next one)
the frame rate dips (that actually caused me to die a few times) even on my "monster" rig, the weird respawn patterns on enemies you need to progress (someone mentioned this a few pages back and its completely true) and other little things make me think the game will end up as "just" another great game (and hey, thats pretty good lol) and not the instant classic I thought it would be during the first hour