I disagree that this is not a big deal. This is a public API in a high-profile library. Any diversion from the norm should be very deliberate  and well thought through. Besides, `await` is not an option in FX4.0. Yes, one can wrap the observable in a task, but you're still adding friction and increasing mental overhead by not conforming to standard practices.

Good API design is about meeting developer expectations. I - and I think most developers - would see `Task` and think "future value". I see observable and I think "future values". Returning observable breaks this expectation and gains you... *nothing* that I can see.

As for not liking the "Async" suffix, nor do I. But so what? It's the standard, so now developers expect to see it for any method that returns a `Task`. Again, given that this is a public API in a high-profile product, surely conforming to developer expectations should be a priority, broken only when absolutely necessary...?

OK, I'll shutup now. Just my 2p.