Saying "here's what you can do with what we have now", as you pointed out, does not mean that all further development should stop nor that someone's suggestion will never be realized. At the same time, assuming that in-game descriptions of powers are "set in stone", with regard to how you, the player, interprets those powers and how they tie into your character, is simply a failure of imagination. As @honoroit pointed out, even dark powers, with careful color selection, can appear as light-based ones. I mean, heck, they've offered alternate stone melee mallet powers that don't use a mallet at all... but that contradicts the power's name! How can this be?