I'd like to see sylpheed-claws use --with-config-dir=.sylpheed-claws as configure-option. Since sylpheed and sylpheed-claws are installable on the same machine, they should not share the same config-dir (they have quite different options). Debian already does this without any problems.
Well, I'm already using it for the (masked) gtk2 build and will continue to do so (gtk2 is expected to become the main branch in the not so far future). Reasons are: - changing it requires users to copy or recreate their configuration manually - The option exists for over a year now and so far nobody has requested a change, so the demand seems to be low (it hasn't existed all the time or it would have been used from the beginning) - I've seen some problems when using the gtk2 build with my normal config, so the separation makes sense - It's always good to introduce such changes together with other major changes (like gtk1->gtk2)