It's a bit easier to accumulate and manage TP than it is MP. If I wanna get TP to function all I have to do is continue to melee or not use a weaponskill that consumes all my TP at once. It kinda depends how much MP that weaponskill absorbs (and the proc rate of it) ontop of how much MP the stances consume.

Marauders giving up defense for their attack boost is only relevant on a target they could potentially take damage from - mainly something with an AoE or possibly a hate reset.