Hrm. The AI can sort of already do this, just not on purpose. It gets ship and guardian unlocks at the start and as the AIP passes certain thresholds. Currently it picks at random; sometimes it picks the worst possible thing for your strat, and other times it doesn't.
You could have an AI type that does not choose at random, but instead always picks ships and guardians that have hull type bonuses against one of your bonus ship types.
Have it unlock new ships twice as often as a regular AI and I think that would kinda cover it.
One problem with the AI unlocking new bonus types it takes a while for the reinforcement mechanic to put enough of the new ship types down to make much of a difference. You could have this AI try to do that more aggressively in some manner.
Reinforcement ship types are heavily affected by planetary type preferences; currently I think getting a tech unlock causes all planets to reroll their list of three preferred ships. This AI type could also be somewhat more aggressive here as well.