Personally what I'd like to see is not a merger but instead another prerquisite that adds all of the standard ores you can possibly think of, For example: copper, tin, zinc, tungsten, gems, uranium, etc. That way all of the mods can have theirs require it and do whatever they want with the ores so that then you don't have multiples of tin and such. I know Eloraam is working on an ore dictionary thing for Forge but this way just seems easier to me.
This, or the "Ore dictionary"
we don't want to force mods on people who only want to play with the one (many people consider mod combos as "OP")
However the mods should still be fully compatible with no duplicate ores and not just these three mods but also other mods such as the still theoretical "Futurecraft"
which will include a good many of the standard ores.