I can certainly understand people thinking the Beta 22, KG dynamic and Millett amps as thin or flat. I'm not sure thin is the word I'd use, but I absolutely understand what you mean. That just happens to be my preference for an amp. I like a livelier source though, and that helps give the system that fuller sound. But I'd rather replace my source to suit and keep my amp very neutral.
There is no reason we all have to like the same sound sig., that's the whole fun of auditioning other's rigs IMO.
Al, your home speaker rig is one of the best I've ever heard, so I doubt we're that far away from each other, sound wise.