I think we should get level 5 at some point during EA because level 5 is when most classes really come into their own. More attacks, more abilities, thing can start to feel genuinely different at that point. Plus I cannot be convinced that we as players can't reach level 5 in act 1. I've seen people talk about killing everything in the Nautiloid and already being at level 3 or something, but even me just playing through relatively normally, I get to level 4 well before the underdark section and probably would hit level 5 before the underdark as well if you do everything on the surface first.
Regarding the throw mechanic, if hitting level 5 makes that mechanic unnecessary, or if the mechanic breaks at level 5, then it's a bad mechanic. Also if the game becomes boring when you hit the point where a lot of folks seem to think the tabletop version becomes really interesting, then they've designed things badly.
