Been meaning to bring up this discussion for a while now, to see what you guys think.
The US Metal Arms trademark recently transferred over to Blizzard and they also initiated registration for such a trademark in the EU.
You can see the US trademark HERE and below you can find the "Prosecution History" section:
Now it's true that Blizzard acquired the developers of Metal Arms, Swingin' Ape Studios, some time ago (2006?), so this transfer is in a way natural and to be expected, however it is weird that it's happening now.
You can see the 4 year gap between any activity regarding the trademark, and there's also the fact that Blizzard has more projects than ever in production. Is this the second still unannounced game, after Overwatch?
I can definitely see them working on the sequel that was supposed to come out before Swingin' Ape was absorbed by Blizzard.