The first level on "The Forsaken" should be upgraded on the first day, especially with Vaishan. He won't be able to take Utopia with 30 mana, but with around 50 mana and an expert summoning skill, he can (+upgrade the racial skill), as he has mines. You're guaranteed to have 30 mana by the end of the first week: 1 at the start + the mana upgrade + the Chamber of Intrigue. Also, you can find an artifact for knowledge (or get it at the start).
On some maps, Vaishan is even preferable to Leto, as he can defeat many neutral creatures with almost no mana, using only stalkers.
In short, I also took Utopia with Vaishan, but later than with Leto. I focused on upgrading summoning, not chaos.