I’ve managed to become slightly more discerning regarding this question since the last time this topic rolled around.
I think more than anything else, I’ve come to enjoy heroines you might describe as difficult women. Trait wise I’m meaning things like characters who exhibit jealousy and insecurity and who are demanding, needy, or greedy. Put into plain words, the above sounds a little twisted, but that’s just the sort of flavor that I like I guess. 2D or otherwise.
Naturally this extends to the archetypes that you might describe as difficult – kuudere, tsundere, and yandere. It also touches on the bookish, shy sorts of characters too. Basically, I like characters that that the protagonist has to either fight for, struggle to build affection with, or work to maintain a relationship with.
Inversely, I’m also particularly fond of strong willed, well put together heroines. Things like big sisters types, upper classmen, and especially older women.
The first type I was explicitly drawn to when I started reading VNs were childhood friend characters. It’s tired and well used, but I like the already present familiarity and sappy shit that accompanies all that.