User blog comment:DarknessStriker/Which support should I choose?/@comment-9048637-20130520180835/@comment-9048637-20130528022215

@Unevent: Yeah, I'd agree. I guess the reason I expressed doubts about jungle Thresh was because I was worried about what his ganks would be like... but now I think about it, they'd probably be pretty vicious - two forms of CC, one doubling as a gap-closer, three forms if his ult is included... his lantern would even be useful for getting his allies in on the business. Though, on the other hand, he wouldn't have access to nearly as many souls in the jungle as in lane, I'd have thought. But maybe I'm wrong. I guess the large monsters are guaranteed soul drops.

Still, more to the point, you're right - people don't play non-support Thresh because, for all that he can do other roles very nicely, he is a truly beastly support. Still, the original poster wanted supports who could, if needed, perform in other roles, and I'd say Thresh definitely qualifies under that category.