I think the desire for a turian/quarian LI is coming from the people who wanted to romance Garrus/Tali with a same sex Shepard, which, you know, goes back to the point I made way back at the start of this thread, that it's ridiculous that the species hurdle, they'll hop without concern, but it's the gender hurdle that gives them pause.
Personally, my preferred list is along the lines of male human, female human, male quarian, female turian.
Actually, for me, I had no interest in Garrus. If I were being honest, I'd say that what I really would want would be a quarian (mostly because of Reegar) or a krogan (because they are awesome and uber-macho). But since krogan likely won't happen because most people wouldn't be interested, turian is my second choice.
My strong reaction against drell simply has to do with the way that they are built. They are tall and thin and lithe and space ninjas. As someone who strongly prefers races like: dwarf, orc, half-orc, krogan, qunari, gnome, etc., I just have no interest in drell. Unless we get the rare body-building swole drell who looks more like James than Thane.......
For females, again, I'd prefer a female krogan but......not going to happen likely. So that leaves turian, drell, quarian, and asari. We've already done asari. Still no interest in drell. So......turian and quarian it is, I suppose. With a much stronger preference for turian in this case.