Go kheldian. Peacebringers and warshades can blast and tank. You flip between blasty mode and tanky mode as needed and eventually sort of do both at the same time (although you have to flip-flop between forms to manage aggro). They're the ultimate I Get Bored Easily archetypes - they're not the best at anything, but they're very good at quite a lot.
Typical experience as a peacebringer teaming with brutes as tanks: buff up a bit, blasty-blast, apologise about knockback, blasty-blast until brute gets down to 25% health, shift into dwarf form and take over on aggro-management duty, wait until only bosses remain or brute is back to 100% then go into human form for some serious melee damage then back to nova for ranged damage.
If you have tanks in your team, you'll probably stay in nova (floaty blast prawn) or human mode, but it's handy for when you accidentally pull two sets of mobs - you can fly in, nuke them, nuke them again and then tank out the rest until things get calmer. There's something cool about not knowing what role you're playing until you enter a team - look at the archetype icons in the team roster and think "ah, I'm the tank today" or "cool, I'll DPS until the tank needs help then take over while they recover".
You can hit resistance cap fairly easily and more than double your hit points by pressing two buttons. The peacebringer inherent power allows you to be better at whatever your team needs (warshades get better at whatever your team does) so you never feel like you're just coasting along.