Right, levels 4-14 are currently where the game (3.x) is still fun. I completely agree with the developers on this point, having stopped running games that go above 13 or so myself. They think they can make the game balanced and fun from 1-30. I wish them (and us) the best in this regard, even though I'd honestly be satisfied if the game was fun from 2-22. 
I don't think the 4-14 comment was meant in any way to signify that it would be the default power range, now elongated over 30 levels instead of 10.

I don't think the 4-14 comment was meant in any way to signify that it would be the default power range, now elongated over 30 levels instead of 10.