Doing away with XP would be an incredible thing. XP is so archaic.
Don't see the point of making such a drastic change, honestly, since they already give you what you want at the beginning of every adventure anyhow. There are those of us that still enjoy XP, actually. I know my players very much enjoy the tangible reward at the end of every game.
Additionally, as mentioned already, XP doesn't hinder anything when it comes to progression through adventures. Make more higher CR fights instead of all these APL -2 ones we're getting, include more story awards for roleplaying XP, and you could easily get up to 20th in six books (if so desired). Again, this matters not to me, as I have no problem with them cutting it off at 17th or so at AP's end.
I do so love archaic things! History is awesome!