A critical issue which might arise with Snow Leopard are the characteristics of OpenCL removing flops from the GPU to assist in CPU processing. I have been using the beta and have already discovered some concerns. According to the tech notes Apple has up, these issues will be resolved when OpenCL becomes better integrated.

Something else to think about is that the rumor of Snow Leopard being entirely Cocoa. Right now, there are APIs and frameworks in the beta that are still using Carbon. Basically what this means is that there might be a need to entirely reconfigure applications running on the new system. Catalyst would most likely need some rewrite depending on how radically different the interface.

I can't speak for Richard here but from my own development observations, are that while Snow Leopard will "look the same" to end users, it will be radically different inside and Catalyst won't work quite as well (yet).