>  Besides, await is not an option in FX4.0.

Well, so RxUI 5.x is 4.5 only, so we always have await (in fact, we always have it in ReactiveUI 4.0 too even on Fx 4.0)

> Returning observable breaks this expectation and gains you... nothing that I can see.

Legit.

> OK, I'll shutup now. Just my 2p.

Alright, I'll go halfsies with you, I'll make it `Task<T>` but I still don't want to name the methods `BlaBlahAsync`.