Why leave your shield at home!?

[wind]

Having block with defender I will match up closely with MRD's defender II.
(Glad's can also lvl all the way up for defender II)

Foresight will eat a hit every 30secs, aegis eats 4 hits roughly on avg every 45secs.
2350HP on my glad (would need #'s of a MRD's hp) to vs it
Glad has access to warmonger for AOE tanking, MRD's dont have access to wardrum(30sec aoe taunt)

Lastly, more HP doesn't equal mitigation. MRD are good tanks don't get me wrong but they wont beat a glad as its one of the few classes that is actually unique in its role to all the others.