Is a non-Phoenix route now viable?

It was always possible to start with FO, Nightsisters, or, which probably made the most sense, Jedi. E.g., Qui-Gon lead until Bastila's node is open, Ezra, OB, plus 2. Either that or an Old Republic Jedi squad with Ahsoka, Anakin and Barriss. Later GMY, Bastila and Jolee, plus GK from raids, and eventually JKR, with Padme as a long-term goal.

There are just three giant problems with any non-Phoenix approach: Thrawn, Chimaera, and Phantom II. Thrawn may be THE highest utility character in the game. People currently use him on JKR, DR, CLS and Padme squads in order to beat Malak. He's a strong raid character and invaluable in GA. As for fleet, guilds need all the capital ships players can get their hands on for TW, and Phantom is a staple on every arena fleet for the faster reinforcement. I really wouldn't want to go it without Phoenix.