So, when I started to do my daily analysis, I have sort of realised that I've been giving an awful lot of credit to Johho for making good analyses and generally being helpful. So now I compensated by scrutinising Johho particularly hard. My conclusion is that while his analyses do make him seem pro-town, that's pretty much all that speaks in his favor. He has consistently voted for villagers, which does not have to be suspicious at all, but sometimes (like with the Ketchum vote) he did so out of bandwagoning desires, not any particularly strong suspicions. I think that in the Ketchum case, he (unwittingly or not) helped Aedan and Tonkatoy by switching to Ketchum. Both are unlikely partners, but certainly possible... Also, he explained several times how he could be seen as suspicious, which might be seen as complete honestly or an impressive psychological trick.
Hmm, Johho doesn't seem as clear anymore... though he doesn't have all that much going against him either, those points above are just speculations, possibilities.