At some point UCs start stretching beyond the scope of the civ that is using them, that's my problem with component bloat. How are you trying to pretend like a Hunnic Information Era component, or an Ancient Era American component are anything more than fantasy conjecture? Cultures integrate and meld way too much for that.
I think the better mechanical (and balance) direction would be putting more UC-style elements into policy trees or beliefs. Like-minded cultures will develop the same or similar specialty units, geared towards their political needs. One that jumps to mind: Authority players benefiting from access to battering ram without needing random CS rolls.
The mix-and-match cultures is one of the things I liked about Humankind (but I only played the demo, so maybe it's less interesting after a few eras). But I know the counter argument is that you're starting to just piece together random cultures, and for many players that's not what Civ is about, which I can respect.