I suppose I'll have to RS through bootcamp as a temporary fix. Looking forward to a native OS solution eventually, though. Thanks for all your hard work!
So I'm running into a similar problem. Just got a new Macbook Pro 2016 with Sierra and can't get the toolkit to open. I installed the RSinjector, installed mono 5.2.0.215 (verified it's installed on terminal) and the farthest I get is "Mono closed unexpectedly" when I try to boot up the actual toolkit. Older versions of the toolkit won't even give me the message and instead doesn't open anything at all when I try to run the app. Any ideas?