There are multiple ways to win and you can set the victory conditions in the new game options. One is through prestige, another is a tech victory, or you can just crush your rivals etc.

I don't think the criticism was on the Prestige Victory itself, but on the lack of knowledge explaining it to the user. That much I can agree with. Frankly most of my understanding of the game comes from previous GC titles, I can't imagine a player unfamiliar with the series trying it out for the first time...it would be exceptionally confusing.

Prestige Victory I only understood because of one of the developer diaries. If I had never seen that, and just played the game straight off, there is a good chance I wouldn't understand prestige victory either.

It's called prestige, but really it's mostly a gauge of how powerful you are relative to other empires

With that said, I think it's set too low. I usually have to ignore all the Galactic Challenges (which do actually just give prestige) because otherwise I would win way too early

I just turn off all the victory conditions except "Conquest" since that's the only one that matters to me.  That way nothing stands in my way until I've crushed every other Civ