Unless it has been buffed then Gruul wasn't especially hard here, server first guilds roflstomped it in pre-raid blues with a few epics thrown around, you should have a hunter or two above 1k dps though, as they can reach those numbers on Gruul quite easily in pre-raid gear with a few Kara bits. You also want to pre-assign rough positions for the entire raid, pre-assign healers and get your melee group to decide which dps get's to stay on the boss during shatter (so that they aren't fighting over it and killing each other).
Ideally use a Warrior main tank with a Feral offtank, make sure your ret paladin (if you have one) is ready to use Lay on Hands on the tank towards the end if needed. Melee dps are strong on the fight but if one of your tanks dies then so does most of your melee dps, so you can be better off more ranged heavy and so long as they are out of melee range they won't get hit by hurtful strike when one of your tanks dies.
Our guilds kill here on Outland a year ago.
With blues, greens, couple epics, only T4 was open on the server.
Really depends on how you're doing the fight, if you're tight on dps you absolutely cannot afford to waste dps like this because you're paying for it at the end of the fight. Just put it this way, none of the good guilds killing this in low end gear when it was current sacrificed melee dps in this way. The boss is absolutely huge, you can fit in a couple of players within the hitbox range during shatter without much risk, two of those positions are taken by the tank (to avoid hurtful strike risk) and that leaves room for a Rogue to stay in for the shatter.Melee need to move AWAY from the boss. not run straight back into melee range when they get thrown.. DPS need to be away, spreading, DPS during shatters doesn't at all matter. It's a survival based fight, if you live, the dps check is easy (it's like, what, 700 dps per 17 DPSers to kill it before 15 growths? That's nothing.
On our video above we had one dps warrior staying in on the shatters, it pays off.
You do not need people in T5 gear come on don't be so ridiculous, you need blues + kara/crafted epics.. With the T5/T6 BOE crafted stuff and S2 gear from Battlegrounds now you can massively overgear this fight just with a pre-raid set. You forget that on retail we didn't have 2.4.3 classes and powerful easy to make crafted gear available at launch, a lot of Warmane fights have more health than retail, but the 2.4.3 talents + higher average gear level more than make up for it on the majority of fights (gruul included).