I mean, not having the legendary cloak hurts, but that shouldn't make or break things based on what you're describing.
I think it's mainly ability usage. The difference between a good warrior and a great warrior is how effectively they use their toolbelt.
So to start off on H-Galakras... I almost always engage that second tower mob with a cooldown, whether it be demo shout or shield wall or last stand. Sometimes if the healer is behind he can just face you. Secondly, you can't block that mob's attacks, so having shield block up is pointless. Use all your rage there on sbar.
Since you can't have 100% coverage with shield block, the judicious use of shield block and shield barrier is very important, you need to switch them up based on whatever your current situation is. When you're not tanking it's sometimes good to let your shield block charges regen.
From a DPS perspective: with the riposte/avoidance build hitting revenge as fast as possible becomes very important, but make sure you keep up your sunder stacks. Shield slam is by far your highest damage ability and it hits REAL hard when shield block is up, managing vengence, intervening on some fights if it's save to do so to keep your vengeance high can help. So yeah, try as much as possible to shield slam with shield block up if you're focused on DPS.
Your gearing/build though - the avoidance build is NOT better for tanking and you WILL feel squishier, peroid. If you feel like you're dying a lot and are taking too much damage, go full mastery (up to 89% unbuffed, which will be 100% raid buffed) before going back for more parry.
Secondly, you're kind of doing the avoidance build wrong. You have a LOT of dodge. The thing that makes avoidance do a lot of dps is that when you parry your revenge does 50% more damage due to the Hold The Line Glyph. This does not activate on dodges. Subsequently you're sabatoging your damage by stacking that much dodge. If you go with a riposte build you should really go all-in on parry. You can stack it pretty damn high without anything bad happening.
So, TL;DR: if you're worried about DPS: go Parry (And frankly for HM-25 man you can do this until H-Siegecrafter, for 10 man you can pretty much do this build for the whole tier).
If you're worried about Squishiness/Dying: go Mastery
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