First, the background so you can put my comment in perspective:
My guild is a mix of f2p and p2p. We launched the normal difficulty immediately when the raid launched. Currently, we have 87% remaining on phase 2. Rancor raid is about a 45 minute free-for-all to take out from full for us.
So far, I'm enjoying the new raid. I'm looking at it as a growth challenge, and as it providing some direction in what teams I will be building over the next several months. Is it taking longer than I would like? Sure. Is it harder than I was expecting? Yes. But I don't have complaints about those things.
The devs created a new raid that would not go down in a way that was even remotely as easy as the Rancor. Good. The reality is that in 5-6 months, we will be taking down the heroic in an hour, and waiting for the next raid to come out, because whatever new things come out will make this easier, the way mods made the Rancor easier. That's the way these things work.
As far as the litany of complaints about how the top guilds and biggest whales will all get GK and the people who can't get him will no longer be able to compete in arena, that's b*********. Every time there's a new character with a solid kit, the cries of "no one can ever win again!" come out. I don't know how many threads were on here about how shoretrooper would kill every meta ever. Guess what -- he hasn't. GK is going to potentially introduce new metas, but he's not going to destroy every other team out there.
I will agree with two complaints though. First, I think that it would have been nice to have an "easy" tier for smaller and/or newer guilds. Second, the animations are soooooooooo slow. The tank needs to get through its attacks at least twice as fast. Other than that, I like it.