So, I've discovered that more is not necessarily better.
After a bit of experimentation with Exerelin (by which I mean, I attempted to drop mods into it, not realizing that I would have to write fleet scripts for EVERY mod faction, not just ones that specifically notated it in their OPs), I decided to just come back to SS+ and, instead of sticking with just the four integrated factions, added about a dozen.
Now, I'm a big fan of variety, but even with balance issues aside... this is kind of ridiculous. There's something like a dozen systems, with Corvus itself loaded with like 4 factions; my newsfeed is constantly mentioning one convoy or another, and I find myself distinctly lost as to what to do with myself. I can't decide on a 'main' faction like I could in SS+ "vanilla", and unlike with SS+ with the normal amount of factions added, it's a lot harder to just say "oh, hey, I can take on this faction's convoys now, I think I'll make them one of my enemies!"
On the other hand, the game has never felt nearly as expansive.