Abstractions, whenever possible I think, should try not to conflict with names in extended, even when the patch is designed for vanilla. Also, I think it's helpful to include tilde in abstraction names when audio signals are involved.
Also, I forgot to mention that I think abstractions (and maybe to a lesser extent subpatches) should follow the right-to-left conventions of Pd objects for input/output, even if it complicates layout on the parent. So for instance [gate] from cyclone is bad Pd style, IMO, and an abstraction designed to mimic it ([gator], say) should be set up more like a multi-outlet [spigot]. Even [timer] still bothers me, but I guess it's a special case.
Matt