Right now, Aux is fairly useless by comparison with the other three power levels. I would suggest that Aux power affect ability cooldowns (not global or shared). This could be done on the same scale as weapon power. That is, at 0 Aux abilities stop cooldown entirely, at 25 they have twice the normal cooldown, at 50 they cooldown normally, at 100 they cooldown in 50% of the time. If double speed cooldown is too much, perhaps 100 Aux could result in 75% cooldown time. This would affect ability cooldowns only, not global or shared cooldowns which would prevent the worst attempts at "chaining" abilities.
Aux to SIF and aux to battery skills are alot better on test server now. So alot of people will switch from engineering team to Aux to SIF, except on cruisers and healers of course. If they add some secondary effect to aux power levels, it will be even better.