As funny as it is, I don't see a major issue with this. I mean, no, they're not going to be able to pursue through a wormhole and so are of limited overall strategic threat, but things like this offer a certain level of extra tactical difficulty at the local level both in terms of the initial attack, and, should you lose the planet, your own counter-attack. The idea of having the AI spawn one or more player-type Superfortresses is even more painfully amusing.