it is not uber-easy but I think it can work while we find a solution about quikstarts. I personally don't feel the need for it, but if anyone want to add it I'll be happy to test extensively the feature.
I'm aware that's the current syntax, I just think it's a bridge too far for most people still tho.
It requires you to know that the system needed a special cd cart, and it requires you to know 2 device names, and know that MESS requires you to specify both.
the 'easier' (?) alternative might be to add a dependency system in the software lists, where every CD game has the CD card software and device listed as a dependency, so if you don't specify one directly it will use the listed dependency instead and tell you that it's done that. However that's less flexible for other future uses.
Multi-disc games will sill need a way to recognize software / media as being related to the current software, not currently mounted to a device, but available in the internal GUI as related media. There are one or two SegaCD games which are multi-disc, so we'll probably hit that once they start running. I guess there are already things with multiple floppies tho ;-)
While MESS will never be quite the plug-and-play solution that most console emulators are (due to the documentation aspect, and wanting to support real correct sets + document what was released etc.) I still think it's important that usability is brought from 'Brick Wall' level to 'MAME' level. The recent changes do a lot towards that and the fact that MAME merging is even feasible a testament to it :-)