I really think they should get both, but whatever. The only thing is Polistes is that the TEC ogrovs can take out starbases well, but trinity Advent and Vasari antistructure cruisers are either non-existant or ineffective. Granted it sounds like one Advent titan will have the ability to capture planets through Auxillary government, so that will negate many loyalist benefits, and what I assume are the Vasari loyalist seem to get the ability to bring something in addition to their titan that can help in that setup, but that still leaves two factions with a hard time dealing with this situation. The old counter of bomber swarms won't work well against a titan.
That said, I agree the best thing to do in that situation is the outflank them. There maybe situations where that's not possible, but you should have most of the map by then, and thus its just a war of attrition. A very painful one but you should have won at that point anyways, and with the new victory conditions it may not be necessary to fight through them.