Testing "ruler" mode:
So far things I noticed:
1. when you found a colony you create your own faction automatically, you have to give the colony back to the comissioner to fix it.
2. colonies don't show on the colonies screen, so you can't administrate them remotely, and most interestingly, they don't count against administrator limits in any form, in fact it feels op, you can administrate infinite colonies and get +1 stability from management bonus, also you have no limits on administrators.
3. you can purchase governorship of colonies you already "own", feels silly, maybe this option shouldn't show up at all in ruler mode.
4. the colonies get a market even without commerce industry, this can be OP, but at same time might be useful. But you don't get access to "resources" screen. (since to me that screen is useless, I never found what it is actually useful for, I prefer it this way, w ould want even if vanilla did this).
good things that I noticed:
1. you are default administrator of that faction colonies, as expected.
2. you can form factions
this is biggest feature I wanted out of this actually, I believed it was impossible, found out with this feature it is possible, this is awesome. would use this even if just a workaround: enable feature, form faction, disable feature again.
3. IFF seemly works correctly.
4. faction diplomacy seemly works correctly too, other factions wanting peace for example show to you the peace screen correctly.
EDIT:
maybe governorship is necessary after all... got zero income from colonies.