I think the aura idea is interesting, but I have to disagree on the commander being the weakest. Here's some ways I plan on using mine:
* RENEW, and bring a healer along with the power creeps. Paired with an executor with HARVEST_ENERGY, the healer can tag along indefinitely, and avoid the need to return home to heal power creeps.
* SUMMON isn't as obviously useful for harvesting as Executors, but it essentially lets you replace the CPU cost of moving a hauler creep 48 steps across a room with a single action. This would be a huge CPU savings Seems like it could also be useful in combat situations.
* Being chased down by a sniper / killbot Executor? Put SIGHT on your own Executor and kite / instakill them.
* Being chased by a group of boosted creeps? Keep hitting their healer(s) with EXHAUST and force the attackers to stay back or risk getting shot down.
* BERSERK + cloud of snipe executors.