Yeah it's obvious he won't be joining in the forseeable future, WWE has been good to him why risk it.
A waste to who? TNA gain another household name and potentially if used as a tag team, then one of the most popular tag teams ever.
Incase you mean a waste in terms of his own career, then I think TNA is the right move for him, he isn't getting the spotlight and will be waaaay behind in terms of an IC/US title shot, younger, better guys are ahead of him, McIntyre, Rhodes, Ziggler, Kingston ect ect. He also talks about wanting to settle down more and be closer to his family and living in Orlando will be a lot closer to S.Carolina and he will get to hang out with Shannon Moore and Jeff dailly at work, perhaps forming a stable. It's a no brainer than TNA will be better for Matt with his personal issues and also for his career now that he finds himself well down the card and also burning his bridges with WWE.
IMO Christian should be back in TNA too, smaller pond but I'm sure he would rather be getting attention, wrestling in PPVs and having the chance to win belts. WWE is very much moving onto this new younger wave of talent and it is pushing some established pros down the pecking order.
As for the "they" I sadly feel like it could be Nash, Sting, Hall and Steiner backed up by Hogan and Bischoff, which will surely fail but also if it was done correctly it might be half decent.... still hope thats not it though.