It's an interesting idea, to say the least. Here's how I see it though:
The WWE employs men and women under huge contracts to go out and perform in front of massive audiences, and do what they love for a living. They pay most of their travel expenses, medical bills, and even have rehab programs for people that need healing in other areas. It's not perfect, but the WWE does a lot for the people on their pay roll. Do I think John Cena has a better health care plan than the rest of the guys? I don't know...do I care is the better question... The point is, all the WWE asks for in return is hardcore dedication to the company, to your job, flexibility to be on the road all the time appearing whenever they want you to, and the humility to do what the writers ask you to do. Once in awhile they may put special limitations on people for unique circumstances. But come on, it's the WWE. If I had a job there, I wouldn't be complaining about a damn thing. You don't see Big Dick Johnson all over Twitter complaining about WWE using him incorrectly EVERY SINGLE DAY! (yes, that was a shot on Matt Hardy).
The only person that I don't think deserved to get released is Mickie James. Maybe she had an attitude, but who cares? Everybody in pro wrestling has an attitude. She didn't lose the weight, and they fired her. Personally I never really saw an issue with her weight, and she was still the best in the division for many years, and will probably continue to be better than anybody currently on WWE programming. But even in that case, I'm sure there was stuff going on backstage that nobody knows about.
Daniel Bryan got the boot because he couldn't follow WWE's PG code. Come on man. It's not that hard. He knew what he could and could not do, and that's that. You work for the WWE, you learn your role. End of subject. And you know what, they brought him back after they made him serve a punishment according to their own rules. It was fair. Serena got canned because she REPEATEDLY refused to not go out and get trashed with fans around. She's playing a straight-edge character... Seriously, she's getting paid 6 digits to NOT drink...For the love of Christ, don't drink... It's not hard. If you can't follow a few rules to do what you have dreamed of doing you're entire life, then you don't deserve to be doing it. I don't feel bad for either of them.
Matt Hardy is a guy who has been with the business for a billions years and still hasn't been in the main event without Jeff by his side. He has now taken to complaining about it over Twitter on a daily basis. But do you know what I think? I think that being in a job for 15 years doesn't qualify you to hold the company banner. Edge, Jericho, Christian, and Hardy have all been in for the same amount of time roughly speaking. Edge and Jericho are future Hall of Famers, no doubt about it. 9 time champion, and best in the world at what he does. They earned their spot. Not by being around forever, but by drawing, selling, and probably doing what they were told. But you can't just be a lemming to get what you want in the WWE. Some people just have the drive and talent to make it to the top. Edge has had several fantastic gimmicks that have made him who he is today... Matt Hardy has been the same guy since day one, more or less. He's never sold more than a moderate amount, and I really don't think Vince and the big boys are too high on him. Veteran status does NOT make you World Champion. End of story. Or else guys like Finlay, Goldust, and Mark Henry would be leading the company right now.
Back to the matter at hand. I don't think there needs to be a union to make sure wrestlers don't get dumped on their ass for no reason. They all have potential, or they wouldn't be there. The boys in Cryme Tyme probably won't go anywhere but the future endeavored pile. They worked as a tag team because of their gimmick, but never got THAT over. Maybe it's bookings fault. Or maybe it's THEIR fault for not proving to booking that they had what it takes. We don't always see what's going on behind the scenes. We see what they show us, and what they show us has kept them on their airwaves for a billion and a half years. So...no...I don't think they need a union. I think they need to man up and do their jobs.