Personally, I think the problem with Lena's content boils down to the fact that, unless you're just in it for the lewd corruption, it's not much fun.
Lena's life is legitimately miserable: she had to drop out of school, she's nearly broke, her friends are often problematic at best, she has no career prospects and now she's the target of a sexual predator with unlimited resources. And none of this is played for laughs or confined to the background. It's bulk of her content, relentlessly portrayed in all the gory details. Ian is pretty much the only exception to this (other than Holly who is still a work in progress at this point). Even Louise feel more like a drain on her sanity than a source of comfort, and the options fall off precipitously from there.
The big advantage GGGB had over ORS is that it didn't take itself nearly as seriously. You could play the story straight if you wanted (staying faithful to Eric, bringing out the wounded soul in Jack, that sort of thing), but if you wanted to throw back and really go wild it was sufficiently over the top that it didn't really register as the same character doing both things. With Lena, we spend so much time establishing her mindset, her backstory, her stats, even how she's seen by Ian, that it's hard to really fit both extremes of the character into the same game.
Ian does have some of the same problems, but it's mitigated by his less precarious situation and by the way his friends (including romantic options like Allison and Holly) seem capable of making his life better rather than adding as much angst as the they remove. I respect the craftsmanship of ORS, but there aren't a lot of scenes I replay just to enjoy them again.