I see. That is a pretty big bunch of hurdles to get over. Regardless, for whatever it's worth, here are some thoughts. (TL;DR: play at Hard or Path of the Damned.)
The trash mobs were thinned out in 3.0. It's still a bit repetitive in places but IMO now no more so than in, say, IWD. So this is a little improved at least. However, what difficulty were you playing on? Normal is so easy that it's possible to grind through all encounters by repeating one of several rote tactics, which makes the whole thing feel dull and repetitive. Hard is hard enough that you need to shake things up sometimes, and Path of the Damned actually forces you to think about what you're doing, vary tactics, sometimes use consumables, and so on. I.e. I suspect at least a part of your perception of it being repetitive may be due to playing it at too low difficulty setting.
The XP thing is a matter of preference, so nothing much to say about that. If it's a showstopper, then that's what it is.
The "porous party" thing I don't understand at all. It's much less porous than in the IE games because of engagement -- on tight maps your front line will hold until knocked out or disabled, and on open ones intercepting a unit headed for your second line will actually stop it. This has in fact been one of the things most loudly criticised by the people who hate Pillars combat. The AI in 2.0 and 3.0 has been noticeably improved, so they will go after your softer targets more aggressively -- i.e., if you couldn't protect your squishies before, that'll be even harder now.
"Stats and skill" - the diff between the IE games and Pillars is that in Pillars all/most of the bonuses are linear and additive rather than multiplicative. I.e. the difference between a 12 Might fighter and a 20 Might fighter is much less than between a 12 Strength fighter and an 18/99 Strength fighter. On the other hand, the difference between an 8 Might fighter and a 12 Might fighter is bigger. So if you're looking for the huge swing from "practically unplayable" to "hammer of god," you won't get that. The differences are still most definitely there. The most visible one is Intellect: try rolling up a caster and seeing how the AoE changes between 3 and 20 Intellect. The difference is... kind of huge really. All the stats work the same way: going from 3 Perception to 20 Perception will make you go from whiffing most of the time to critting most of the time, and so on. So it is a real difference, and you do need to recalibrate your expectations if you want to enjoy it. The upside is that it gives you much more levers to pull when creating your character: trading off a few points of Might for a few points of Intellect can make sense, depending on what you're going after.
And dislike for RTwP... well yeah, that's what it is. Still if you managed to enjoy IWD which is basically a big dungeon crawl with about as much plot as your average porno, it's just conceivable that you might find your groove in Pillars as well. But if you don't like it, you don't like it, and I can't see much point trying to force yourself to like it.