I've seen all of those - or read the manga - with the exception of that heroine thing and Further than the Universe (and the new FLCL but I have no intention of sullying good memories). Well. Flip Flappers I've only watched after the comment here but it's precisely the sort of thing that I wasn't asking about - genki girl meets bookish girl ... I mean, it wasn't that bad. But also kinda meh.
Same for Izetta. I was positively surprised by a bunch of characters dying but it's still this very "anime gurrrls doing things"-like production.
What hit the spot better was Devilman Lady, actually. I mean, it's older, but I must have missed it back in the days when I watching more ;) Features an adult, bi-sexual heroine who (among other things...) clearly has something going on with a high school girl. And her ally/enemy is MtF. It's precisely does not that stupid one-dimensional character trope rubbish ("oh look, another tsundere!") but has (...by anime standards) nuanced, realistic characters that slowly develop over the story.
Alas, it's pretty crappy. Particularly the action scenes are just rubbish (and there's a lot of them). And the end is kinda "let's just completely go off the rails 'cause this is an anime!" sort of stuff. But, still. At least it tried!
I'm currently trying Red Garden but the pace of that thing is driving me up the walls. Look at how ... nothing happens. And still nothing happens. Let's go to the other girl. Oh, nothing happens. Well, what about this girl? Also nothing happening. Let's have some more nothing happening ...
Anyway, thanks for trying. It's appreciated :D