Sadly, they kind of took the ambiguity out of how they are going to deal with the giant robot. Seriously though, Kuvira's boyfriend was a bad enough engineer that he wouldn't notice sabotage, but good enough to build that monstrosity /while/ working on recreating the spirit vine weapon? Either a lot more time has passed then I thought, or that dude is a real miracle worker, in which case I'd think he would be of such strategic worth that I find it hard to believe Kivira would just sacrifice him in such a hurry.
My guess is he didn't actually designed or built that thing. But hey, only time will tell.
To be fair, there's nothing saying that he just started working on it. After all, even without an arm-mounted laser cannon, a giant mech seems like it'd be pretty useful. And for all the talk about Bataar being a bad engineer, there hasn't really been much to show that.
The only time he actually comes across as even slightly incompetent is when Varick turned the weapon into a bomb on the train, and even then the only thing he messed up on was Varick's intentions. He was able to evaluate the mechanics and design as "feeding into itself" or whatever, he just didn't understand why Varick had designed it that way before Varick told him immediately after.