Also in a randomly tangentially related note I wonder how different things would be if decloaking was an action rather than an automatic thing when it it. My guess is it'd be mega broken but I don't really know.
I actually think it wouldn't be all the great expect for maybe Echo. You would lose a lot of action economy. Or you can just run advanced sensors and be like a pre-nerf phantom. No attack dice modification though.
Agent Kallus is pretty good on a Phantom against 2-3 ship builds. He gets worse and worse the more ship your opponent brings. He's nearly useless against +5 ships. I'm curious to see what the crew in Imperial Aces does.
Even in lists with lots of ships there is still a most valuable target.
My thoughts on Kallus are that you want to mark the ship that will be around the longest and be a threat. Against a swarm, you mark one ship and then kill everything else, you'll get the defense bonus against that ship for most of the game.