It'd be interesting if they took a page from LoTRO's book and awarded 'crysta' for earning achievements. Sure it took awhile to actually get enough to buy anything substantial, but I was exceedingly proud back in the day when my hard work earned me enough coins over in LoTRO to purchase access to one of the map packs and a mount. It also works in SE's favor because there's still going to be people who will be antsy with the slow gains this system would provide and just jump the gun to buying what they want outright.