Look at the showcase forum. They've got turn-based games, a stylized top-down and other stuff there. True, mostly sidescrolling stuff. But it wouldn't be Spine that would limit you to making platformers.
Given the current features, it should be REALLY easy to do pure top-down like Hotline Miami.
This is a plain 2D skeletal animation system. It's up to the animator to choose which techniques are effective based on that. Shouldn't be hard to figure out. The trial version works well if you want to check what you can make with it.
It's Shadowrun's 45ºish or 60ºish iso that's a considerable challenge. (not that it's any easier if you were doing it frame by frame). The animator would still need to know what he/she's doing or it's easy to mess up, whatever system you're using. Still, it's a matter of workflow and specific techniques. Spine's system supports it, but it won't magically solve your problems by itself, sidescroller or otherwise.
You should download the trial and see if it works for what you need. Aside from the disabled export, it's fully functional.
