Warmind cells are a cool idea but they need refinement like you said. I hate when I kill an enemy and a war mind cell drops but there are no other enemies on the field so I leave it alone because a whole horde of enemies will spawn in a few seconds. Then my idiot team mate blows it up before all the enemies spawn in. This seems to happen all the time. The warmind cells always seem to spawn on the last enemy you kill out of the group so it's either wasted or you have to wait for the next group and hope your allies don't blow it up to soon.