Personally, I want to get the Toa again in 2017. Looking at the summer wave for 2016, it already looks like it's gonna be a hard-fought battle for the Toa and story-wise their armor might be damaged and dinged up, plus I kinda wanna see what the Toa would look like in their "Final Form" to confront Makuta. I still love the United forms, but the Uniters still aren't perfect, and I feel like one last go would give Lego the chance they need to give us even better Toa. I mean it is gonna be the final battle of this Trilogy, so realistically, they would get the best equipment they can get their hands on, story-wise.
Plus then we'll have 6 of each Toa from combining G1 and G2 so they can each have their own team of themselves.
I wouldn't really mind 2017 being all villains, though. But it might be a little confusing since the 2016 Toa would still have the MoCo on their boxes and the 2017 sets will undoubtedly have the MoUP. It'd kinda mess up the continuity of each year's own story arc and the sets that go with it, at least in my opinion. Like, having 2016 sets in the 2017 story would just feel... weird to me. It didn't bug me in G1, because that was 1 continual story, but with G2, so far each year is it's own story arc, 2015 is the MoCr, 2016 is the MoCo, and finally 2017 would be the MoUP.