twistedpony: I'm in a similar boat to the OP. For me, I think it was the dated mechanics of BG and PT that annoyed me. In BG, I hated how resting in the wilderness was punished by ever spawning enemies and yet if you don't rest, you run out of spells fast. But in battling the spawned enemies, you might use up more spells and hence make the resting pointless. Area effect spells don't show you what area they would affect. Equipping a bow for every party member was handy for softening up the enemy before melee and yet it was tedious to switch weapons. In the end, playing it seemed more of a chore than fun. Or maybe I just sucked at it. The story, though, seemed interesting. PT's story and characters was also interesting but the combat was really boring. I probably would have completed it but stopped playing at one point and never went back. Too hard to pick up again since I've forgotten what happened.
I loved KOTOR2 and NWN2 and its expansion, though, but it sounds like Pillars of Eternity might be a bit more old school than those. I do tend to prefer fully voiced dialogue, although I appreciate that it then limits the amount of branching dialogue that can exist.
I didn't play the original BG until recently. I played BG2 when it came out, a couple times, I like the story a lot but there is a lot of overcumbersome combat IMO and the roleplaying is to be desire IMO, as interesting as the ROLE you play going good or bad is, it's not deep role-playing at all. But I could never get through BG because the few times I tried over the years the respawning of the mobs killed it for me along with some other iffiness of the interface, but most of all the respawning. But now there are patches and mods that fix a lot of the issues, as well as having the ability to turn monster-spawns COMPLETELY off (the #1 thing that allowed me to play it, finally), you can also use the BG2 UI and updated engine, which really just makes it that much smoother of a play and actually allows getting into for me. However, they are still just good+ games in my book, BG2 being the better game, but both just being good, nothing great. The story is told really well, that is what is great about it, and if you like a lot of combat for a lot of time, that is also great, but for me it becomes a bit much to get through to get at the adventure and story.
I recommend at PS:T, Arcanum, Fallout 1+2, and now Inquisitor and consider them to be must-plays and think they deserve mention wayyyy before BG/BG2 (which I don't consider a must-play, at all, it's a "must play if if if") , to me they aren't even the same calibur of games. There are other games I'd recommend before they BGs as well, and I'm not suggesting you play BG/BG2 but I do suggest the others. Maybe you should just play PoE and let it really get you into the genre and then go back and play these classics, but, that is almost blasphemy, but hey, whatever it takes! Start PS:T over, become a mage ASAP (best way to play the game, and best combat, IMO.) If needed turn the difficulty down and play it easier.
As for having a hard time dealing with "dated mechanics", I really think it just takes a little time and getting used to them and if you allow yourself the patience for that you will get huge rewards. They just have a bit of a learning curve more than most because of the complexities and the not-perfect implementation of everything and their unique styles.
As for PoE, it is probably worth trying, but read some information, watch some videos, give it some time for more information and videos to accumulate and find out more about it, you'll probably be able to tell if it is for you or not. If you have difficulty with the type of game because of the character building aspects, just play it on an easier mode. Don't worry about learning how to build a great character so you can be badass as possible, play a main character you will find fun in a fun way and enjoy.