I think a WXP booster would be an excellent addition to the game, in the same vein as a PvP Glory booster, Gold Booster, Karma Booster, etc. Honestly I was a little surprised nothing like this was added to the cash shop in the March 26th update.
On the same point, the WvW community is very overlooked in terms of cash shop support. Sure, we have the finisher consumables, but honestly not many people (at least in higher tiers and in hardcore WvW guilds) are going to stop for 3 seconds just to drop a cow on someone else. For example, a “Bag of Siege Plans” that gives 3 pieces of siege that require less supply to build.
Fifty Bladesof Gray – L80 Sylvari Thief
Little Brown Bags – L80 Asura Necromancer
Stunbot – L80 Sylvari Warrior