Ultimately this seems less like Mattel having a niche to itself and more like it gets to pay for the entire party it arrived late to. I've collected all the Super7 and Playmates reissues I wanted. The NECA turtles haven't got much left in them (granted the Sakai ones surprised me, but I don't see yself picking up Usagi or any others in this style), and the 3rd party stuff is mostly where my money was headed under Rage/Fury Toys. $50-$65 a figure seemed like a lot until Mondo and then Mety/LingjiHun came along. Now we're debating which is better, HeatBoys or MetyToyz because they're so similar in many ways. I honestly don't know what niche this leaves for Mattel to try to wow us with. The McFarlane comics ones didn't garner my interest or my money, so I doubt Mattel will either considering as how none of their MOTU stuff called to me. The only angle I see this affecting me personally is if Mattel thinks it's going to lock down the license and leave everyone else with theirTMNT lines incomplete in many ways (except for perhaps NECA). How it handles companies like Mety/Lingjihun and Mondo will determine what if any good will I have toward Mattel. I think a lot of people were already moving on from TMNT so for all we know Mattel's foray may actually push more to bounce out. Or not. I have no clue what they're doing, I just know I don't need any more "homage" figures to original released modified in whatever way to make it appear modern while still looking rushed.
There's nothing I can directly point to that I want from Mattel specifically other than "diversity of the line" meaning all the different turtle companies get to continue their stuff and I'll see if Mattel's even looks cool. If they're gonna be the TMNT monolith and push everyone else out I don't see this taking off beyond the main 8 or so figures...and then the wrestling mashups start...