Chrono Trigger's Death Peak wasn't too bad for me, but one thing I have to add is you have to fight a few Lavos babies during the climb, too. Those little bastards are the kind monster with the "two targets, but you will feel a lot of pain if you attack the second target" dilemma.
Hey, it could have been worse, though. The monsters could have been weak to lightning/light. Since Magus is your only other option for a lightning user (besides Robo's highest single tech) and he could also be long dead, it could have blown (hehe, puns) even more. Or, maybe even some battle formations would have a monster that gets more aggressive if attacked with the element every other monster is weak to. It would be like the Ocean Palace Scouts and the need to concentrate on them all over again.
I can also add another JRPG to the list: FF7. The whole Great Glacier sequence blows (a lot of frigid air). You got the confusing pathways (which where you can get or permanently miss Alexander, so don't forget to grab everyone's favorite mech/castle) right after the snowboarding minigame. Then there's the blizzard section with the player having to try and walk in a straight line, watching Cloud poop out little marker flags to indicate a change in direction, while the camera rotates around constantly. Right after that is Gaea's Cliff, which isn't all bad, but it starts out with a body heat retaining minigame during the climb. That would have got really annoying if it went on any longer.