Is a non-Phoenix route now viable?

I would still go Phoenix to start because the beginning of the game is really the only place where Phoenix can be used for more than just getting Thrawn. They won't give you the top spot (whales will always buy the meta off the hop), but they'll keep you relevant until you're ready to move on.

Building a Phoenix team later in the game (like I did) just to get Thrawn is painful even though they're very accessible and easy to farm.