Construct 3 will have a Construct 2 import as well. So I don't think you have much to lose to get it now.
I'd say C3 is quite far off as well, again it's only basically the Editor and not the underlying HTML5 "Engine" that will change.
It will stay 2D, Something I'm happy about, although if someone one day makes a Construct like 3D engine, i'll be over the moon. Unity and Playmaker is NOT it
you already have the Q3D plugin that allows u to create 3d games
im working on a pool game:D and i just use the examples they are out for free
if u play with them u can get whatever u want
even a RPG
.... actually you can build what ever game you like from MMoRPGS to flappy brids , but for now the developer is working on a 3d physics so we can move objects by clicking(for games as pool, pong beer, etc)