Definitely don't agree ... my level 18 party is in Arx and they are getting wiped out in every fight they attempt, it's not even close. And this is in Classic mode.
Same. I found the first part of the game to be fairly straightforward, though it does require a certain amount of doing things in the "right" order, but I found later parts were often a fair bit more difficult. I've never claimed to be a great strategist (because I'm not) which may have a bearing on it but I definitely ran into more problems later on.