Don't worry, there's not much chance of something like that doomcarrier. It was just an example of the sort of extremity to which the AI would need to go to get through the chokepoint "normally"
Right now I'm thinking of just:
- remove the "jumping" effect of warp relays
- having a warp relay, once built, spawn additional threat (proportional to what's already waiting) to join the waiting threat. That way it would in theory eventually have enough strength to punch through without any cheesy tricks, and/or at least make threatballs "self-dislodging"
Actually. With some mods, the Doom Carrier idea doesn't sound too bad.
Image that the Warp Relays could store units, and would trigger free-range-threat/threatfleet to climb in when nearby. When it starts loading, a timer starts counting down. At the end of the count down, the Warp Relay acts like a carrier/Counter-attack wave, teleporting to some targeted system, to disgorge the stored Threatfleet units.
This allows the Threatfleet to perform anti-human deepstrikes, the human gets a (small) warning, and it uses up Threat rather than just producing MOAR UNITS.
Of course, having it slowly produce its own units then launch is another possibility, is MOAR UNITS is what is desired - but that doesn't sound Threat-related, and I think should be a different mechanic.
You could even keep the Threatfleet system targeting logic, just jumping over any 'blocking' systems