A very fun post which makes some good points, points to you, friend.
Having not played Dragon Age, I can't comment on those games. I have played both Mass Effects though, quite extensively, so, here's my personal opinion on the matter.
I don't think Ashley, Jack, or Miranda were that interesting either.
I mean, Jack was kind of interesting (if a bit overwrought) especially through her romantic arc in which she learns to grow up a bit and takes the first steps toward recovery.
Miranda is hot, I guess... I mean not for me, but whatever, to each their own. Besides, she's still animated, so it's hard to actually be attracted.
Anyway, the only thing I remember about her is how much time the camera spent lingering longingly on her ass, in the worst case of pandering in the entire game. Besides that, she thinks she's hot shit but has (maybe) two moments of genuine competence in the entire game (outside of squad member status) and yet still manages to be a "woe is me" simpering charity case.
And Ashley? Ashley is worst of all. An unlikable racist ***** who jumps up to defend her belief systems when nobody fucking asked, and could you please not pipe in your "kill all the freaks" attitude in that snotty tone of voice while I'm trying to be diplomatic? She arrived on the scene as an unlikable *****, and she died an unlikable *****- because every time the option came up to nuke her I couldn't hit yes fast enough*. Kaiden's not much better, but his is a quiet blandness that can at least be ignored, while Ashely can't wait to let her ignorance be known.
* With the exception of one time for story reasons, when she was the love interest of a racist, "humans first" Shepard I made.
So, yeah, IMO, I don't think females are alone in bad love interests from Bioware. And, again, IMO I actually like Thane as a character, as well as a love interest. He's polite, tragic but professional, and spiritual without being preachy.