Definitely credit cap. Restricted hide hat is silly but cosmetic, credit cap actually reduces the market for buying cartel unlocks, since they're tradeable.
How many rich *********** would shell out money on purple gear unlocks if they could sell them on GTN for three million credits each?
Credit cap would make the most sense. It's probably the most gameplay restricting thing on the list.
That said, reward options, reduced xp gains, and inability to equip purple gear all are good targets to be removed as well.