Ingo, I fear that you are overstating the situation m68k is now in. Non release critical bugs do tend to get fixed – if they didn’t there would scarcely be any point in having them in the BTS at all. My guess would be that any difference will be felt mainly when it comes to bodging round problems. I know I fix bugs for ports that aren’t even in the archive (and I don’t just mean AMD64 here) about as quickly as any other bug and I don’t feel that I’m alone on that. Where things don’t get looked at I would expect to see a package that could generally use some more attention.
As far as I have noticed m68k doesn’t tend to have many porting issues that require fixes in individual packages beyond the toolchain and kernel – if that is the case it’s a bit of a moot issue.