Again something that isn't entirely true ... or at least just seen from a pretty one-dimensional approach.
The drum rotation can give a nice, slow background (or bottom) effect while the horn can be perfectly in sync with the song tempo. This is a really nice effect.
Also, all the tempo and ramp speed parameters I keep suggesting make things possible, you don't seem to think of. For example:
Play a solo with a fast rotating horn. Then at the end, you just have a final chord ringing out and you want the rotary effect to slow down to zero over the course of exactly one or two bars. That's what you need ramp speed adjustment for. There's so many things you can do with more speed/tempo related parameters. Just open up your mind a bit and forget about the classic (pretty limited) Leslie. You could even keep that simple Rotary Speaker effect and just add another one with more parameters.
PS: And even the classic Leslie wasn't as limited as the Profiler's Rotary Speaker effect. You could change the drum and horn speed using belt gear disks. Wasn't exactly easy to do, but it was (and is) possible.