This is an extremely important issue for the acceptance of cr2.0 and I'm not convinced its just balance, the advantages given by levelling have be drastically slashed, abilities formerly passive have been promoted to active and can be shut down..this is very unsatifactory and will be interpreted as a significant nerf to all existing players to pander to newbies (this has never been raised as a problem before, genuine newbies dont have a preconcieved idea of what they can and cant affect therefore feel no benefit, MxO already provides one of the easiest levelling curves of any mmo).
The increase of effectiveness of a player in combat must be significantly increased at each level or else there will be no inspiration to level!!