I can never sleep on planes no matter how big the seat. I find all airline seats really uncomfortable when reclined - I tend to slide forward on the seat and need to really tighten the belt to avoid it. In BE, the leg rest kind of helps, but not really. I'm not into the flat bed thing either.

All I ask for is a properly reclining seat - where the seat part reclines with the rest, so that my knees end up a few inches higher than my .... That is a really comfortable position to relax/sleep in. That would not be possible in Y - there simply isn't the seat pitch, but if any airline can provide that in Premium Economy, they'll have my money everytime.