I have wondered about the selective cries for civ nerfing. Why are some civs immune from the cries (Nubia for example) while others are not (Hungary, GC). I am not sure if it is more the multiplayer community calling for the nerfs (ala Souls series) or if some single players actually care about "balance."
You'd think people would want changes to civs because they are boring.
Nubia being OP I think is mostly because their bonuses are actually fairly narrow in scope. Sure, murder archers make them completely dominate the field because archers are so strong early, but the rest of Nubia's bonuses are fairly minor.
The way I look at it a little bit is if you took away a portion of a civ's bonus, would that ability still be fun and useful. For example, with Hungary, if you removed their movement bonus and combat bonus from levied troops entirely, IMO they would still be a fun civ. I mean, being able to levy troops for half price, upgrade them for a pittance, all while gaining 2 envoys to the city-state in question alone makes them a unique and interesting civ, not to mention they also get 2 UU, a fairly strong bonus to districts and buildings depending on city placement, and a favorable starting bias (if you get lucky with geotherms and mountains, you can get some amazing campus spots).
So, I've just removed a strong part of Hungary's bonus, and sure, they may no longer be a truly top tier civ, but they're certainly still way stronger than an average civ. And I look at it a little bit the same way with GC. Honestly, remove their +1 global movement bonus and they're still one of the strongest war civs with guaranteed stacking GG. Or remove the stacking ability from CG/GG, and again, they're still crazy strong. Heck, you could probably completely disable them from being able to get GG (like the Maori or Kongo) and also remove the CG from giving any movement bonuses to units (just combat bonuses and retirement abilities), and they would *still* probably be one of the best warmonger civs out there.