It's definitely not our intend to go into that direction of just paying for increased quality with x-fold rendering times. Which is exactly why we've compromised on things like reflection quality before instead of "cranking everything up" to what's technically possible.
Keep in mind this is still a Preview release and thus a work in process. We'll make sure that rendering times will be comparable to prior releases even with the improved GI quality for the final release.
Personally I would like the option of "cranking everything up" to what's technically possible. As long as lower quality, fast options are also available, I don't see why not.