I'd like to second this, but do realize that they're not global so we can purchase them at a cheaper price. I may not want all of my characters to get the PvP XP bonus unlocked - just one or two of them. This method allows for that to be done at a cheaper price.
However, I think it should be offered as an option (at the appropriate price).
I like this idea -- an option for a (probably hefty) "lifetime" price to unlock a perk for your whole Legacy, vs. per-character purchases. Perks like the XP gains make a lot of sense for individual characters (if you play them differently), but stuff like quicker speeder acquisition? Who wouldn't want that across all characters (if you're going to buy it at all)?