So I was thinking about the developing meta that we're hearing about, specifically that elimination of Warlords is likely going to be the primary winning condition (at least at the onset). Now, unlike a few other warlords (like the Astra, SM and Ork ones) Shadowsun doesn't need to be present in order to benefit from her ability. When you commit her, you'd get the initiative and a free attachment. After that, is there any reason to keep her there? Is there a good argument AGAINST just retreating her as soon as logistics allow?
First off, she's a lightning rod for attacks. If you have a FW Elite, that would help but if not then you'll end up throwing any of your shields on her. If she wasn't present, then the best person to attack on your side would be a moving target of "Who's best to attack right now?". That might help spread out some of the damage as you can shield a few damage here and there to keep units alive.
Unlike the Eldar warlord, Tau don't have a card that would require a unique Tau character to be present to use (IE Nullify) except for the neutral No Mercy card, and even then you could play it with our signature character or toss it for a shield instead. Not to mention there are no equipment for Tau that have to be placed on a unique card. And with Shadowsun's staggering attack value of 1, is there a reason to not just withdraw her immediately?