Think it would be pretty cool. If possible (imo) Loop/Enigmatic ascension would unlock the new Loop and Enigmatic buildings and/or Tech. This would be an fantastic upgrade and be something worthy of ascension. To balance this, maybe have a Loop/Enigmatic empire start with those buildings on their homeworld, but unable to reproduce them on their colonies until they take the ascension perk (which would also make some of the vanilla techs relavant in the early game) and require the ascension perk in question to require having taken at least one (maybe two) other perks before taking the Loop/Enigmatic ascension path. This way ascending your empire into Loop/Enigmatic would truely become a massive shift that changes your entire empire into a new glory age of Loop-induced goodieness. If you wanted to go all the way you could even space the Tech/Buildings across two ascension perks, one into to get some basic tech and another for the advanced ones like the vanilla ascension perks.

I would feel adding in a new ablity with ascension would be better

I think shifting some tech into ascension perks would be good, as you can 'ascend' to the level of the Enigmatics.