Might as well just keep going with what you're doing. Some things may be better left dead, but who cares? I may not personally switch to Permissions 4 after already upgrading to PermissionsBukkit, but people who loved what died will continue to use it as long as they can, and maybe new people will hop on who wish to feel a bit nostalgic. Take hMod as your example. Despite having been riddled with ignored bugs and entirely dropped by hey0, it was continued for what seemed like forever by Meaglin, and now sits quietly as Canary Mod over at canarymod.net. Resurrection, ftw.