Tekkit: Platform is still being tested but if Mael's up to it when it launches, he'll be able to customize the modpack, adding and removing things and put a custom launcher out for everyone to download somewhere. Ditching some redundant mods and adding Thaumcraft 3+ when it's a bit more full-featured would be kinda cool. TC3 even has an option to regen chunks with the new TC blocks without having to scrap your world and start again or go off looking for new chunks.