Brayflox shouldn't really be an issue for Gladiators. Especially single target, since you should have Rage of Halone by then.

Personally, I find the only time I have trouble tanking is multi mob packs where DPS split targets instead of attacking the marked one. And Flash isn't an AoE provoke. It builds threat sure, but it isn't guaranteed to instarip aggro plus it costs mana to use. If your tank is having to keep up rune blade for mana regen instead of Rage of Halone for single targets, then you're gonna have a bad time.