A game focused on bettering yourself or discovering yourself is a really neat concept; I'd love to see that in more games.
As for my preferred antagonists, my favorites are either villains so human that you can understand their actions, even if you consider them wrong, or inhuman villains so far from empathy that they inspire terror. Villains that exist as people who make bad decisions, and monstrous villains that exist purely to create evil. As many have mentioned, some of the best villains see themselves as the hero of their own story; who often have similar goals to the hero but make more extreme decisions. Personally the villain I'd like to see more of is the monster, something old and evil and motivated by nothing other than destruction. I'll point to tropes such as genius loci, where the villain is a sentinent island/school/world so much bigger than the hero. Or some creature from another dimension seeking to wreak havoc. It may sound cliche, but I've come to enjoy villains with no other motive than to shake things up (well, as long as it's well written enough). Then again, villains with understandable reasons for becoming villains are pretty good too. In the end, though, I think it really depends on what kind of story you're aiming for. Sometimes pumeling an ancient and powerful evil back to the horrid dimension it came from is good enough
The antagonist of Hotel is an evil sentinent hotel, of course