Warrior in Frontlines

[Phenidate]

On your first point: Every 60s you get to pop a free 200 potency AoE or a 300 potency attack that ignores your damage reduction. MRD without the damage penalties out does that in a single Eye/butchers combo by close to 200 potency.

The tanking benefits of Inner Beast only comes into play when you're being attacked, and Second Wind + Featherfoot are used to reinforce there.

This is irrelevant, since any good WAR would turn off Defiance before spamming Overpower for AoE damage in PvP and would do so after using their Wrath stack in some way. WAR potential AoE DPS is, in fact, higher than MRD's.

If you turn defiance off you lose the use of all WAR weaponskills until it's turned back on. You can not accumulate wrath. You're reduced to using MRD skills and your meager selection of cross class skills.

A MRD can overpower for longer than WAR can. Invigorate, Enliven, up to 1250 potential TP at your fingertips to WAR's 750 (assuming you specced enliven). Internal Release, Raging strikes to boost your damage past what a WAR can do. Since you said defiance is off, you lost your crit stacks.

Edit: And I think the take away here is that compared to a PLD, WAR is an inferior tank for his team; no blinds, no tetsudo, no cover, no stoneskin, no spammable stun to use on everyone around you and stunlock for 6s until DR resist kicks in. Counting on damage to kill dps and keep your healers safe? Compared to a MRD he is inferior in both burst and sustained DPS.
WAR suffers in Frontlines and Arena. Luckily, all WAR are a crystal away from MRD.