But the Pride demon is supposed to be a tank. And if it can make an ability go to waste it is filling the roll of tanking, combine that with the loud, obvious telegraph and immunity for the second it is applying it's guard makes a certain amount of sense.
The pride demon is weak because it doesn't do anything valuable, it takes no thought to deal with, or not deal with as you can just run around killing it's allies while it stomps around slowly.
If it could absorb damage, and nullify powers even for a split second it would fill a role.
The RTC can go into his invincibility frames quickly enough that they can foil attacks that would have otherwise been held back (The best thing to do is sandbag the fight while watching his health bar. In order for invincibility frames to not be overly cheesy, there needs to be significant tells leading into them). The thing is, those invincibility frames are a carry over from SP, to ensure that the fight can't be ended before going through his three phases. That is the one and only reason that the RTC is the way he is in DAMP (well it certainly seems that way).
I guess it would have been too much work to make the fight as it should have been (no invincibility frames for the RTC). So, that being the case, invincibility frames really should be minimized in DAMP. The pride demon should get a beefy durability buff, in the form of either HP, greater max guard, increased armor, or perhaps a combination of all three. Anything is better than putting more lame invincibility frame crap into the game.