Instructions don't mean compatability, at least on my A600 or A1200 I never has to do anything more complicated than loading a previous kickstart. My PC on the other had was constantly making me muck about with installation and drivers.Neither platform was ideal but the PC wasn't the rosy home of development you're making it out to be (-;
It's funny you should mention the ST/PC disc compatibility - I remember someone trying their ST copy of Nitro on a school RM Nimbus PC and it getting at least as far as the title screen....Loading a previous kickdown wasn't really that nerdy, all I knew as a kid was with some old games I had to put my 'kickdown' disk in first before they would run, its only in the last few months I've discovered it's actually loading a different version to RAM (-;If I has the room I'd get an ST I think, they certainly have enough different about them to warrant it.
As you probably know there were plenty of dual format disks for games both Amiga/ST disk and Amiga/PC too, there was even a few Tri-format disks with all 3 formats on 1 disk! 3D Pool was one of them!