The Sleep spell caught my attention -- twice.
But then thinking on it and reading it again this morning: Was Sleep written this way in the playtest? This spell is much more powerful than pre-4e (I did not play enough 4e to know how good it is). As long as a critter is not immune to Charm you just beat on it until it has around 20-30 HPs and Sleep it. No save. I did not see a Coup de Gras rule in the Basic, but even if the DM is strick that still means everyone can gather round and get a free attack on a prone sleeping creature. Kinda feels like an anticlimatic finisher for the BBEG. If I am understanding the magic rules, the Wizard could then just Sleep the beast again if it somehow still has HPs after the first attempt to finish it off (and they have an open slot).
(lets be honest with ourselves - one of the players will know the relative HP level of some of the big bad critters - I guess Giants will need their own Bag or Rats so the sleep spell knocks them out first

).
In the end, this might be OK as it keeps the Sleep relevant even at high levels. As a DM it would be fun to Sleep a high level party that is on the edge of a TPK and finish them off with a Sleep spell.
But otherwise 5e looks like a lean, mean system!