A little off topic, but just an interesting mechanic that I just thought of: wouldn't it be neat if missionary vessels (maybe the other colony frigates too, but come on, it's called a missionary vessel for gods' sakes

) could generate culture like a mini-deliverance impact? It could give them an interesting combat role, providing mitigation bonuses where your culture can't reach, or somewhere too far away to perform a tactical deliverance shot.
As to culture itself, I would enjoy some other effects as well, such as allegiance also affecting planet HP (an unruly/rebelling population would be easier to subjugate under the guise of "freeing" them from their former oppressors, no?).
How about spawning rebels? (I know, they're pretty much useless, but it would be a nice touch)
What if orbital structures had a chance to flip after allegiance has hit zero? Or maybe very low allegiance could lead to crew/popular rebellions which could disable or destroy orbital structures or garrison ships? This wouldn't be as drastic as planet flipping (which I presume was removed from the beta because it didn't work well?), but would certainly give more credence to a culture-oriented strategy.
Wasn't there a bug related to this that once a planet was neutralized, the extractors would produce at 100% even if the max allegiance there was lower? I can't remember specifically...
One thing that I think absolutely has to be added is an easier way to monitor culture than allegiance and the colour of the phase lines. I think there should be a small chart in the info card for each planet which displays what percentage of the population is loyal to whom. It's just annoyingly hard to tell whether your culture is actually having an affect, or exactly when a planet will flip to neutral.