Something you can often see being discussed in Chosen class forums is what's better, great weapon or sword and shield. It seems that the majority of players believe that for most situations the great weapon wins. I'd agree too, sort of.
Sure there's loads of situations where you want to be using a shield and there's also plenty of decent specs you can go with, but most of the time (and with the right gear) you'd be better off with a variant of the cookie cutter Dread/Discord mastery spec.
Other than in Fortress or large keep battles (where every extra bit of survivability counts), we're just not really encouraged to use a shield. Unlike the other tanks, Chosen have no abilities that effect block and only have 2 things that even relate to block. Those being an aura with a heal proc on blocks and a tactic that boosts your parry if you block. The Corrupting Retribution aura is so poor it's barely worth having on your action bar, it is truely terrible. The Mixed Defenses tactic is good, but it's boosting parry, not block. Since parry only effects melee, it does not compare with abilities that increase block. Other tank classes all have ways of increasing block chance, which dramatically increases their survivability. Chosen do not have any.
We do however have ways of increasing our parry rate. Supression, a standard trainable ability has a mere 10 sec cooldown and increases our parry rate by 25% for 15 seconds. Also Chosen with great weapons can get very high crit rates, 30+% is easy to reach and with that spec it means you'll be reducing everyone with 30fts damage by 25% with every crit. Since that effect lasts 10 seconds and you'll crit multiple times within that 10 seconds, it's effectively a constant debuff. By stacking strength you can hit very hard for a tank, but you're still able to stack enough toughness and wounds to be difficult to kill. You are squishier of course, by not using a shield you probably missing around 30% block which reduces a lot of damage, but it is nowhere near as bad as people think. With 700-1000 toughness, decent armour value, resists and our parry buffs, a Chosen with a great weapon can still be a tough cookie indeed. BTW you don't need a shield to use the guard ability either.
As such in a lot of situations you might be missing the 30% or so block on frontal attacks, but you've gained a 25% damage reduction on everyone nearby and you're doing a LOT more damage. In this age of bomb groups, that's pretty damn effective.
So why did I only sort of agree?
Maybe I'm a mentalist, but it's a bit dull with a great weapon. Sure you get to see some big numbers, get to actually kill players, are not ignored by enemies, apply an awesome debuff and are generally a very effective uber killing bastard, but... (lol but he says :P ) I like having some of the other abilities that you can't get with a great weapon spec. Things like the silences from Tzeentch reflection (hitting that and hold the line for 85% disrupt and silencing anyone you disrupt is nice...), the stun from Downfall and of course Hold the line. It feels more sort of tanky, if you know what I mean. The problem is at heart we know it's just not as good. I think this is why I change between great weapon and shield specs every single week, like the littlest hobo I just can't settle down.
Perhaps we're meant to be great weapon tanks. After all, Chosen is the only tank without a block buffing ability and our most powerfull damage reducing ability is reliant on critical hits and is from the Dread (great weapon) mastery. Maybe Mythic are telling us something...