Personally, I think that the stacks should either be removed, or the gains from stacks be more about unlocking a passive. Increase the base stats a bit, have the stacks be for the passive (such as soul eater), and boom, you have a bit more power for the first buy without putting yourself so far behind that when it comes online, your not already irrelevant.

Not saying it's a perfect solution, but the current form clearly lacks appeal.