I'm not sure Memory is a good idea. It's not the idea of limiting your skill slots that I object to - it's having to spend previous attribute points to increase your skill slots.
Especially at the current trade rate of 3 attribute points = 1 skill slot.
It really depends on how may attribute points you get on level-up. In D:OS 1, you got 0.5 attribute points on level-up. I'm pretty sure that you have to be getting a lot more than that in D:OS 2. They certainly can't give you only 0.5 or 1 attribute point a level and expect players to actually use the Memory attribute.
