[obligatory I took second place with The Winnu last game they're not that bad post]
That being said, I think the proposition to give them access to anyone one tech opens the flood gate for absolute abuse. While I agree Cruiser II would absolute fix what is seen as the "Sardak Start" in my playgroup. I think that this is a balancing mechanic against them. [Incoming Anecdotal Evidence] I held Rex the entire game, and only through keep away and over expansion on my part did I manage to only take 2nd place. Hegemonic Trade Policies is absolutely absurd. I understand that without Cruiser II they don't really have a chance to get there at any decent speed. But the threat of you taking Rex so early without influence is a potent one. One that will make players either break their bank trying to remove the token for themselves crippling them for a turn, or forcing them to park expeditionary forces just to slow you down.
While this post will most likely surprise no one but I think they're fine as is.