Yeah, the IWDs are the "less talk, more fight" of the bunch, while PS:T is the exact opposite. And yes, has possibly the best writing in a game.
Fun thing in IWD2 with the Battle Square, there are enemies that may be too big for the door, so I kept reloading until I got one if I saw it was possible, got my ranger out and just pelted with the regular endless arrow. But not sure I could complete all of it actually, can't quite recall.
As for the final battle, it was less bad than I feared, but I might have just done the right things. Recall just having my cleric duke it out with one of the bosses while the others ganged up on the other, cleric sadly getting erradicated just before the other's health got low enough for them to surrender, but so be it.
Also believe the average party level worked in my favor throughout thanks to the party, wizard and cleric being tiefling and aasimar, for the +int/wis, and having the 1 level penalty. Also meant they didn't have level 9 spells by the end, but worked without.
And I also played IWD2 first out of the IE games. Then had a look at IWD1, saw the smaller inventory space and said nope, loot management was bad enough in 2, and this combat-heavy approach wasn't enough of a motivation to struggle with another frustrating element.
Played PS:T in 2009, finished at the start of 2010. Some months later started BG1, struggled with it on and off for some two years, been abandoned since then, thinking I may return to it but probably not by this point. Didn't play BG2 yet. As for ToEE, just had a quick look and gave up after one fight, not keen on how it worked.
Morrowind, probably started in 2008, if not 2007, definitely stopped in 2008 the first time, then continued for a little while in 2012, and just like BG1 it's been waiting eversince, though I have some more intent of eventually continuing it... maybe... if the constant respawns and low vendor gold wouldn't annoy me so much. Didn't try Daggerfall. Tried Arena a bit back when it was initially made free, made it out of the starting dungeon, wandered through the city a bit, went into the wilds, found another dungeon, decided it was too simple and random and pointless and gave up.
NWN, started in 2007, finally finished all of the Diamond edition content on Dec 31 last year.
The first Witcher, ah, still fond but also frustrating memories of that one. Started in 2013, finished in 2015, kept feeling that if I did one thing I broke three later, but sure liked how combat flowed (though many dislike it) and how it showed it was a labor of love.
As for Arcanum, played way back, in 2002 and 2003. Sure restarted it lots of times, optimizing the levels, since companions annoyingly need to be recruited right at the proper time, seeing as their starting level is fixed, they won't join if you're more than one level below when you ask and will level when you do, so if you're above them they'll lag behind throughout. Bad memory of Black Mountain Clan Mines, quite a slog there, but nice otherwise... Until I got stuck in Tulla, simply could find no way to complete something and advance. Pity... (But watch for bugs, Troika style. Also had restarts, or at least reloads from several hours back since I had been overwriting saves, because of cursed items that left the stat drop permanent after removal.)
Overall, I'd say you're in for some good experiences, if you can put up with some of the frustrations :)