I found a champion exploit: two Human Shadow Destroyer w/three shields can hold off an attack on Home command pretty much indefinitely. I recommend a 2-second delay before modules can be built.
What difficulty?
I mean, it may contain one wave, but if in the process the ai is tearing up the rest of the galaxy your power will likely go out from losing planets, and even if it doesn't the second wave will get you, champion or no. It may not be able to die, but it's dps can't hold back 1k waves.
Keep in mind the cost of 20% extra everything on the ai. It means squat under 200 aip, but then you start to feel it...
That's a problem with the champion. There is a lack of pacing. Under 100 aip an extra 20% means almost nothing. 200 aip an extra 20% is a little noticeable. 300 aip and I feel the balance point is approaching on cost vs. effect. 400 and above it isn't worth it.
Is it possible to do something other then a strict % increase in aip? Like, for example, the champion costs a smaller percent but a hidden extra aip that increases per hour but caps at something not insane.
(20 aip * number of hours but caps at 100 total aip) + (7% aip)
This would make it that early game it would cost more, in that for ultra low aip games you really feel it if you try to keep the aip floored. But the raw increases take 5 hours, and while contribute to ship count don't contribute to ship mark composition (meaning if you had 150 aip in the hud and an extra 100 of the hidden aip, the ai wouldn't send MK II ships but would send waves the strength of 250 aip.) So champions cost more early, however, champions shine most early game.
But late game the champions don't shine so much (they don't do as much against 2k waves as 500 ship waves) so a smaller % increases would lessen the sting.