I suggest making the config generate the common mod ores. Considering 1.7 does not use block ids but uses block names, this should cause no issues and should make life for the user easier. I suggest adding default support for IC2, thaumcraft 4, railcraft, AE2, factorization, and TCon. Thank you for takingg this into consideration.

wouldnt it be easy to allow a "auto configuration", so simply look through ore dictionary and add a dense-variant for each ore?

I think the best would be a way to auto-add ore dictionary ores, with a blacklist option in the config. This way, when new mods release/update/add ores, RWTema doesn't have to update accordingly.