I don't feel that bringing the player to the edge of winning/loosing and letting it there really fits into the AI War's meta: there is, OMHO, a grander sens of progression and clear phases in AI War (early game, scouting, opening / mid-game, conquest, increase in power / end-game, big final battle, result of past decisions).
The reason I pointed it out was because there's a certain threshold where the game is
exciting because you're kept in suspense, just shy of being able to win or having lost, but aren't
pressured by anything other than the fact that the win is juuust two moves away, if only you'd be allowed those two moves.
AIWC tries to pressure a loss by throwing a CPA or Exo at you and while, yes, there's the sudden excitement about "ooh, this might be the one that kills me!" when you survive you're not left in a state where you can make a move towards winning. Instead you're rebuilding back towards a state where it'll happen all over again. A constant cycle of "near-loss, rebuild" erodes the tension.
If we take the analogy to Jenga, a sudden CPA is like getting your turn only for your friends to switch on a fan, creating a sudden cross-breeze that makes it impossible to take out the next piece (or just outright knocks over the tower: you lose!). Only if you manage it, then it's turned off for their turns. At some point you're going to call someone an asshole and walk out.
The difference here is that
the player's action dictates the tension: removing a tile from the tower might be the move that ends it, but if not, the game continues. The next move draws the Sheep from an opponent's hand, giving you the resource you desperately needed. The dice come up 9, getting you the stone you need. Doubles, roll again. Sure, there are some random elements involved, but they
appear to be under the player's control: the player is the one rolling the dice: "Big bucks big bucks, no whammy no whammy!"
As opposed to "I'd like to kindly remind you that you must
pay the bank 80,000 credits before Saturday." You need those credits to keep playing and need those credits to create still more credits. Constantly being knocked
back to square 1 isn't progression, it's stagnation.
I don't know how to make this happen in AI War. The only similar mechanics I can think of are more appropriate to a zombie apocalypse: enemies
just keep coming. Imagine that an Exowave is just a constant stream of units into your worlds, an unending tide (obviously at a strength level more close to that of a standard wave). Now it's a pressure that can either be kept at bay or will, eventually, overcome your defenses and take you out. You can't dedicate any of your fleet to solving this problem, because any units you do send are going to be there indefinitely. They aren't dead, per say, they're engaged with the enemy, permanently, reducing the amount of ships you have to make attacks on other planets. You can't repair (effectively) because your engineers just get shot, but the repairs you do make exactly equal the amount of damage you're taking. You can't forget about it for very long, but you have breathing room to focus your attention to other tasks.
Hmm...maybe I did think of something.
(This is the TLDR)
Take that idea (prior paragraph) and put it into play. The attacks will stop when you accomplish a task...say, completely removing the AI from an entire solar system. The waves start when you gain a strong foothold (say...a third of the planets?) and doesn't cease until you control all of them. (Note: the waves would not come from the same direction as your advance, or you'd be unable to send your fleet in to perform further conquests. The continuous waves would be a 'diversion' of sorts that would allow the AI to make ingress back into the system, unless your fleet fights it off and captures more territory).
If you've expanded into multiple solar systems at once, you'll get multiple waves you need to fight off simultaneously. Perhaps you've overextended. If you can't handle the pressure and capture a whole system quickly, you're going to lose (the combined assault overwhelming your ability to repair faster than your ability to conquer).