I for one will definately reserve Berserk helmet and Herod's shoulders as warrior tank.
I will not have punk hunter stealing it from me who can wear a leather headband thats even better statwise.
Suck it up. I'm in demand as a tank, I can make rules and when people are willing to come along I'm glad to take them along - but the zerker helmet will be mine!
Hydra: I think you didn't quite grasp the whole thing: It's not like the reserver EVERY item. Take the faster run speed sword from Baron Rivendare. There might be a warrior who is raiding AQ and they are in desperate need of the last couple % dmg for twin emperors. So the warrior starts to farm the sword in order to stay on the boss longer before swapping because he can run faster to the other boss when switching to the sword.
Now he will grind this item possibly for weeks nonstop to get the last couple % dmg.
He might be willing to take nonguildies/nonpremade (which is unlikely but thats just a situation to show you how it works). He will now write reserve on said epic sword but you will be able to roll on the blue +agi Axe which is a nice tankitem for newer players, the awesome shield from Rammstein. So you aren't left out of all items. Just the one which is desperately farmed for.
Now you can deal with that or you can make your own group and dont make any loot rules. It's up to you and nobody is forcing you.
I hope my example showed you this properly.
Cheers.