It's not like fully BiS p2ps with full 5.4 chants will be running around the gulch in groups of 10 in every game instantly when 5.4 hits... Just try it out and see, probably the decent f2ps will still stand a good chance against most 24s, and nothing's gonna change that much. P2Ps had the upper hand before, they have it now, they will have it in the future.
Hardly any of 24s even right now are even near bis, why'd they be in 5.4 when some of the best enchants cost thousands of gold? 24s generally don't do too well against somewhat coordinated groups anyways, they're not gonna suddenly absorb some magical gladiator r1 powers when patch changes and they get a few chants more to crutch on.