User blog comment:Big Lupu/Why do wards take slots?/@comment-4022742-20130608225531

You need to have wards as items, because else you'd just make support obsolete for a major part of their role. You'd have too much vision late game, so much so that you can just get rid of fog of war.

It would also result in everyone stocking up pink wards, and then battling it out for vision, instead of pushing towers <- your actual objective.

Giving everyone a ward slot is a bad idea. Giving everyone that specs enough points in utility an extra "ward slot" could be done, but is still a bit awkward.