I don't watch a whole lot of other Minecraft players, mainly just CaptainSparklez and X33N, so I don't know who I'd say for sure. What would be interesting, however, is if ilmango or gnembon joined. With their crazy farms and machines, I bet it could be interesting to see what they come up with. I suppose it would be nice to throw pixlriffs and zloyxp some love, considering how much they put into the Recaps and let them play.
Oh, this just popped into my head. What if each hermit held a contest, whether a build-off or whatever, on their community servers and each of the winners got to play on season 6 with their hermit. Maybe keep it interesting where the "guest hermits" would have to compete by giving an "offering" to the "hermit gods" or whatever each week to stay on the whitelist. For example, the first week they might need to give a block of diamond, week 2 a stack of iron ingots, etc, and keep building it up until only one remains. Well, maybe not season 6, but could be an interesting mini-series.