No one has reported a significant shortening of game times. Yet. In general the 4UC mod adds a fair amount of culture, but there is relatively little additional science. Cultural victory has been slowed down considerably as a result.
There are 3 civs with ultra late UCs which are intentionally given game-enders. Korean Chaebol is an overwhelming yields snowball, Japan's battleship has immense steroids, Brazil's infantry make a tourism bomb on kills. I haven't actually heard back from anyone re: late game with any of these civs
More UCs means power spikes aren't as big, and are more spread out. This shifts the meta more towards defense. Militaristic civs have a lot of UC overlap to compensate for this (Sweden, Songhai, Zulu, Russia, Rome, Huns, Denmark). Time will tell if it's enough to counter stagnation.
Players have reported that Zulu is breaking the game currently, but he's doing that in base VP anyways, so we aren't sure if it's us.
There's more 2nd-tier faith civs now (Zulu, Carthage, Germany, Polynesia, Songhai). The kind that won't win a faith game, but are all at least nipping at the heals of slow faith starters like India and Maya.
4UC did not shy away from making components at least as powerful as base VP assets, unlike EE which consciously made underpowered buildings to offset inflation. This is one reason why I'm skeptical of using both mods together. Heaven forbid you add E&D on top of that as well.
