'Dro is easy just stun or root' OK and if I don't have those...........
Literally every class in the game has those. This might shock you, but you MAY want to rethink your talent selections when faced with adversity, rather than throw your hands up. All specs are not created equal, so maybe respec and do it (it's not like your dps is REMOTELY important to finishing the scenario), every class can with RELATIVE ease in some way or another.
If you post your class, I'm sure plenty of us can help. Nobody minds helping. It's irritating to read tons of posts from people that are literally "THIS IS BULLSHIT ITS IMPOSSIBLE" "Try thing A" "I DONT WANT TO TRY THING A" (IE: priests). That's not constructive to the thread and it's also willful ignorance on the part of people posting that kind of shit, if you want to vent about something fine, but don't be surprised when people give you advice.
I got SHREKED by Dro the first time I fought him (well, my withered did, I was a tank so I myself was ok, but that's strengths and weaknesses again), becoming familiar with it is part of the learning curve of an event like that, or anything in the game really. It's not any different. EVERYONE dies to that guy the first time. The difference is how much people are willing to be introspective and critical of how they can improve, just like with raiding/dungeons/everything else in wow. Everyone sucked at everything once. The people who do better at it just didn't throw their hands in the air.
If you have to take withered training slowly, take it slowly, have some CDs for every pack by all means. As you get better at it you'll feel out where you need em and where you don't. The best way to beat Dro and every other boss in there? Get used to how they operate so you can minimize losses, and have LOTS of withered with you. Set them to berserk. That's it. That's the trick. 30 berserking withered will melt Dro in like 15 seconds. If you're feeling timid about how many you've got vs a new boss you don't know, send some chests back to help for next time. I'll tell you right now: If you can beat dro, you can beat the entire thing easily. None of the other bosses are as hard. I fucked up BADLY today after having it crash on me last time, and I was pissed, so I decided to safely send out every chest but one, I had 1 withered left. Found 1 more, killed the last boss with just 2 guys, because once you understand how they work it's easy to keep your guys alive. I absolutely agree that it's harder as some specs than others, but I don't play my main spec in there either, so people can throw a fit about it and pretend the talent specialization menu doesn't exist for them, or they can hit N and select 'activate' on another spec, and look at their talents and figure out what helps more. It's all about control and survivability, not dps.
Two withered with near 0 hp, just casually throwin rocks at a spider for 2 minutes while it struggles to do even 1 damage to me. Just learn Dro, you'll melt the rest of these clowns.