The only Bioware games I've played and enjoyed are Neverwinter Nights + expansions etc and Dragon Age Origins/Awakenings.
I remember trying Balder's gate once many moons ago and just not getting very far. I can't even remember why. I might give this another try at some point though. Balder's Gate 2, however, intensely triggered my party formation OCD by having my companions just wander off all the time, drove me nuts and this is the sole reason I quit the game soon after the Beholder cave and have never been tempted to try again. I don't deny it's a good game, I just can't personally bare that one singular mechanic.
I tried KOTOR and played for aaaages and nothing of interest had happened and the combat was waaaay to laughably easy to hold my interest, so I quit soon after sneaking past that Rancor that was unfathomably placed in some random hall. I also had no idea what was going on nor what my motivation was supposed to be, either because it wasn't there or what was there was too unbearably uninteresting to endure listening to.
I haven't tried Mass Effect yet to any great extent as I'm an FPS 'hater', so it seems logical to not bother trying.
Dragon Age 2 was such a joke of a game combined with being dull as dishwater that I only finished the last chapter out of morbid curiosity, literally clicking on any random dialogue without reading anything and skipping any skippable cutscene, just to see how asinine what plot I could follow turned out like. I was encouraged to see some hype for part 3 which seemed to rectify the problems of 2, but upon the game's release it just had most of the stuff I didn't like from Origins and barely any of what I did like combined with being a halfbreed MMO, and I'm not buying a game where only 25% of it appeals to me. I tried to watch a let's play of it instead on Youtube, just to get the story but I even had to quit that soon after that cripplingly bad singing set-up/scene followed by numerous dull strolls around stargazing towers in banal empty wildernesses.
Having said this, I even found the OC of NWN to be somewhat dull and dragged-out when it was first released, but at least it had a solid 'feel' to it, as in good mechanics, loot, environments etc. I was relieved to finish it. If I replay it now I can go quicker and treat it like a solid aRPG which isn't altogether too bad. Loved the expansions.
And I liked Dragon Age Origins but more in a guilty pleasure kind-of way, in that I could see it was a bit shit but still seemed to have fun playing. I'd say this was Bioware's best ever narrative for a full length game, it's just such a shame it came post-D&D and had the start of the more tarded gameplay mechanics that we all know and love today. Like NWN I enjoyed the expansion a lot more.
So I've always been kind of 'meh' to Bioware and remain to this day still kind of 'meh' to Bioware, and, as more of an outside observer to Bioware fandom, I can say it's quite amusing seeing how the mirror has reversed in the last 10-15 years, from Bioware fans being the dominant RPG force that mocks 'crappy' RPGs like Icewind Dale (really, most of the BG 2 fans wouldn't even look at IWD as soon as they heard it had no companions, but now love to include it as an example of the good ol' IE days, because it helps their argument) to being the mock-fodder of all mock-fodders, lower even that modern equivalents of IWD.
I'm not amused in a spiteful, vengeful way, just in a "ain't life weird" kind-of way.
As for answering why Bioware has become the mock-fodder, wow, that would take quite some walls of text!