Giving 50% EXP perks does unbalance gameplay btw, as exp = AA's, and AA's = better player. Giving unique best-of-tier Augs do too. At least with Lillu's mug of EXP it's unbiased random splurts of temporary 1 shot EXP, but when you give incentives to donate that make your character better that is technically unbalanced.

Other than that, welcome, we have talked quite a bit before you joined the team, and we'll likely talk a lot more from here on.
(Some suggested non-balance altering things is 'weapon molds', where players can ask to have their weapon transformed to a graphic of their choice. Unique titles. Stuff that gives zero benefit in game other than aesthetics, like the clicky illusions with no added component bonuses).
Most games have a form of item malls anyways, so I guess I shouldn't be surprised. At least you can't buy epics and armor. But balanced is when donating gives no benefit in my eyes. Right now I know I'll always be 1 aug short of the best no matter what until I donate. XD