If our cash shop is going to be anything like the Japanese Cash Shop, there's going to be a LOT of stat boosting items and items to help enhancing. Clovers that give 50% increase, prevent breaking. Clovers that give 100% success rates, etc. CS items that increase magic attack by 30% for an hour or two, ones that increase physical attack for an hour, movement speed for 30 minutes, etc. etc. etc. List goes on. There's also fashion items in their CS. Only way it could really "ruin" the game is if they priced them really high. =x ( Ex: $20 for a skill reset. Damn you gpotato~! )
In any case.. I've never really seen CS as a game ruining thing. Since most of the time, if not always, you can buy them from other people, which for the most part puts people at an even playing field eventually. One could argue that you don't have enough gold to buy from other people; but in this game gold is relatively easy to get.. unless you're below level 20, which you probably shouldn't even bother spending on stat boosting items cause it's so easy to level anyways. >_>
ANYWAYS.. yeah.. My thoughts on the CS system.