Hey clueso, nice to see you on DFans. I agree with the anti-elemental standpoint, which a number of players/posters have taken (across both forums). In theory, it would be nice to have gems relating to each elemental damage type; unfortunately, the runes are simply not balanced well enough at this time to make them an attractive option. Take the case of cold EP for example; there would be no reason to build around any other element. The same could have been said for ET - Raging Storm pre-nerf.
To make this concept work properly, each element would need to serve a specific function, with each elemental gem boosting said function across the board. The foundation simply does not exist at the moment, which makes the prospect seem unappealing.