Actually, I think the Homeworld difference between DL and DA/TA has come up before in threads since I've been here, perhaps even with Mumblefratz and myself noting the delta. But, perhaps I mis-remember.
The AI empires have not seemed to get another capital colony building anytime I conquer that planet of theirs, even though a new planet visually changes to be the capital. What happens to that building once I conquer or flip it. That is, do I now have two such bonus structures? Anyone know? I cannot check myself until tonight.
Note, that if I now have two such buildings, even if only one is my official capital, that such would be another exploit. That is, in a current game I am slowly conquering an AI right now (the Drath, who I always seem to end up fighting). Each time I take their capital, a new one spawns (but it does not have the extra bonuses). If it DID get those bonuses, than I could end up with many of those buildings. If the building bonus does NOT respawn for an empire but does remain after being conquered, then a player could have as many of those buildings as there are empires to conquer.
That is, if one could move/redesignate the capital, then the respawn upon conquering would seem to naturally follow. Thus, a careful conqueror would have that exploit available.
In fact, one could carefully work an enemy down to one planet (which would by default be a capital), gift them a planet, conquer the present capital, have the gifted planet become a capital, gift them another, conquer the first gifted planet which has become a capital, etc. One could rinse and repeat until every planet one had was the capital bonus building!
I suspect that a conquered capital loses its bonuses. I doubt they return even if the original owner re-acquires that planet, but i have not yet tested that. Anyone know?