I guess for me there’s a difference between a guy who murdered a bunch of people (who wouldn’t even be there if Jacob didn’t bring them all there) because he’s stuck on this weird crazy island with weird nutty island mojo and the title EVIL INCARNATE who’s going to destroy everyone around him. He definitely did everything to manipulate others (which is also something I find annoying about both MIB and Jacob - being all manipulative and all Zeus like deciding people’s ‘fates’ - be it through killing them or luring them to the island) into doing what he wants, and did some terrible things like killing a whole bunch of people - but you’re right, it is for this one and only goal - leaving the island after being trapped there for centuries. So in that sense, sure, he’s a bad, bad dude. But in a way, not superhumanly so, just humanly bad - pretty much any type of garden variety human murderer with issues (but also a murderer under some pretty weird circumstances that was set up by whatever game Jacob was playing with him).
The problem I have is that other than Jacob’s word (that MIB will destroy the world if he leaves), I don’t think the show did enough to show me that indeed is Smokey’s end goal, and that he is some sort of a master devil who’d destroy the world if let out (and would succeed). Given this guy, smokey or not, had been stuck there for centuries, I can see his entire goal was just to escape the island and get his freedom - which was expressed lots throughout the show, once MIB found out his home isn’t the island - and not some world domination/destruction goal that Jacob believed to be. So, at least for me, I don’t think it’s completely far fetched that in experiencing the real world outside of the island without crazy mothers and weird island mojo for the first time in ages, that Smokey will cease to be all smokey like and function like any other guy (and be obsessed with the iPhone4, or porn (hey, here’s a guy who’s been sexually frustrated for centuries too! No wonder he’s poofing around killing everyone), or something!).