I had a 1996 MC1 with C tranny’s and I didn’t find its mids to be any better or more Marshall-y than the 2016 MTL I still have with V tranny’s and like you said I think the tonal differences probably had more to do with the model differences. The mids sat higher and was more pronounced in the mids overall, but the quality of tone itself in that range was still equally hollow/bland and smooth/lacking growl to my ears. I think that midrange tone is just Wizard’s Achilles heal (all amps have their own lol), but otherwise not a whole lot else to complain about. No amp has it all. My 1972 SuperLead 100 brings the mids, but shallow low end quality. Imho I t’s not internet lore, just I think guys like myself playing them, comparing them to other amps and evaluating what we’re hearing. it’s only internet lore for those silly guys that only judge amps based on clips lol
My Wizard has been a keeper for 6 years now, it’s a phenomenal amp no doubt, but I totally get how that midrange thing can be a dealbreaker for some. When I used my amps for my friend’s re-amping 2 years ago, without me saying anything to influence his opinion, we tried the Wizard and immediately he said it’s too hollow, not the sound I want (I though it sounded quite good though myself). Then we tried my 1979 JMP2203 and Naylor and he loved both and said that’s the sound, much more harmonically rich. He’s not a gearhead or even much of a guitarist, but he’s a great composer with very good, discerning ears. Just my long winded 2 cents lol