But that PvP gear is no longer available, which means characters below level 55 before 3.0 will not have access to it. The number of characters wearing PvP gear in the 30 - 59 bracket is going to fall dramatically over the next month. SWTOR doesn't have much of a twink community like other PvP MMOs (AION, for example) and very few players are going to hold off on purchasing the expansion so they can remain in that bracket permanently.
Also, most of the good PvPers will be aiming to get to 60 as quickly as possible so they can start gearing early, which means they won't be wasting their time in the 30 - 59 bracket forever.
This is a short-term problem that will fix itself. Making changes to the level brackets because you're upset that you couldn't get your solo kill in a levelling bracket is ridiculous and BioWare will never go through with such a plan.