I just grabbed my lvl 24 sorc. Using gear that is way better than any casual would have, it took me 2.5 hours to respec from Lightning Blast to Fire Bolt (level 9)
As a "beta" tester, there is no way I would have devoted any time to trying out different builds (at least low level, maybe its worse at higher level, I don't even want to try) if it took me 5 hours to try something interesting and then go back. So I think its reasonable to assume that a lot of build beta testing did not happen that could have.
But forget about beta, that is allegedly in the past. Now if we're talking about post beta. A casual player would probably take a weekend, or maybe even a week, with crap gear, to try a different build with this system. A player with not much time, in D3/D4/POE/etc, would take minutes to try a new build and decide it wasn't for them. I think that's a problem in a type of game that is about builds.