Consumes should be used in two situations: (1) where you may be mechanically sound on a boss (not perfect, but very good) and you need consumes to get you over the jump, and (2) for speed clearing when things are on farm. On our first BWL we wiped three times on Razorgore just to make sure people knew their roles and the fight mechanics and after that we all popped consumes and cleared it easily, just as an example.
I think people underestimate how big of an impact not using consumes can have. Even yesterday we cleared from 2nd loot dragon to Nef, everything one shot then moved into MC and had a really shit time on Lucifron because almost no one used restorative potions and a shit load of people ate the massive shadow damage. We didn't need to use heavy consumables because we didn't know the fight, just to save the effort, and when people don't save the effort when everyone expects you to it can get hairy.
Also, had a huge night last night, Stormrage gloves and empowered leggings (i can still keep 3 piece as a result of getting the gloves which is fabulous) and a herald of woe which is going to be unreal for when AB rolls around. That's the kind of night that keeps you in business!