Elladan, along with his brother Elrohir, is somewhat despised by most players because for one to work, you need the other in the same deck; severely limiting the options. One of their best uses is in a fellowship with the twins in different decks, but that brings up the problem that they're not Ranged and Sentinel. I do think the brothers can be very powerful if you can work them in, especially once you build up their resource pools a bit. One thing of note is that with the new ally versions in MoF, there are now new interesting combinations for the elven twins.