They should try out hybrid classes again. I always felt pugilist could have a 2nd job as a tank. There is no reason to add a -damage modifier as missing every positional should take care of that.

I think the core mechanics would work like warrior. Replace GL with some other stack that improves survivability (evasion, parry, hp% up, damage reduction%).
To prevent breaking the light armor theme of the class, they should also, like warrior, get hp and healing % increases.

Monk is perfect to me as a pure dps. A second job (blackbelt maybe?) would remove all monk job skills (fist of fire, Dragon kick etc) and give plenty of room to add more tanking skills. Then the enmity+ for basic skill would need to be tied to the job (for low level dungeon purposes)

Ps.
I made this up on the spot