I will admit that, yes, it does seem likely that Paramount may prefer for DC to just permanently hold the license. Though IDW will probably continue to publish TMNT comics for as long as possible.
The main hopes for DC not being the publisher are:
- Paramount don't really consider TMNT a comic book franchise (which they probably ought to, I hate it when FW is treated like the start of the franchise, but may be preferable for this particular scenario) and may just license it to some other publisher, like Warner already does with Adventure Time and Rick & Morty.
- DC just not being interested in integrating the property.
I've said it before, DC getting TMNT essentially means nice reprints of old comics but will mean a drastically reduced comics output. They're probably only going get like five issue minis once in a while to keep the trademark going, maybe a pessimistic notion but a sadly plausible one.
My biggest fear is that TMNT will be reduced to what most DC heroes were in Batman the Brave and the Bold, present but ultimately just bit players. In particular there is an episode of that show that show in which the Doom Patrol appears and the premise is essentially "What if we do the self-sacrifice story that ended the original run... But we make Batman take centre-stage despite not even being in the original story?". Can you imagine that? Like the TMNT appear in a Superman cartoon or something and they do the Space arc with the Fugitoid and all... But then Clark Kent is the real main character or something and the only reason it plays out mostly the same is because D'Hoonib has a red sun or whatever? And that's the only time in the entire show the TMNT show up? That's a very real possibility.