Mesmer/Chrono other roles
From what I know, it’s now almost mandatory to have 2 Mesmers in a raid group, so one will be tanking and the other will be focusing on DPS (on top of keeping quickness/alacrity up of course).
Kiss the chaos.
Chrono can provide other buffs like permanent protection, fury etc (in fact all of them with exception of might and things like resistance). Condition mesmer shows good results with enemy like Matthias.
It’ perfectly fine to have a tank that isn’t the chrono. Druid tank, guardian tank, necro tank, thief tank, honestly you can tank on pretty much any class if you spec it properly. The main thing, however, is that the difference in playstyle between a non-tank chrono and a tank chrono is pretty minor. The tank in GW2 really is primarily in charge of proper movement of the boss, with a side-dish of mitigating damage to themselves a bit. That’s not nearly as big a role as in other games where need to manage aggro and stuff.
So the better role statement for chrono is more accurately ‘support’. Tank or non-tank, we’re support no matter what.