"A character can fight with both ends of a double weapon as if fighting with two weapons, but he or she incurs all the normal attack penalties associated with two-weapon combat, just as though the character were wielding a one-handed weapon and a light weapon"
Currently, quarterstaffs are the only weapon in DDO that can benefit with this feat, so i would also drop the idea of introducing new weapon types ingame, like Double axes, Polearms (Sireth and Rahl's Might might fall in this category) and such. Its been so long and i think that this game would largely benefit with new kinds of weapon types, new battle animations (specially for monks) and updating how certain feats work (like triple'ing the saves bonus feats, for example... that would make me consider taking Lightning Reflexes)
So... the thing that made me consider adding this feat to the game and quartersaffs is how i picture myself weilding a staff for a fight, using both ends to try and land hits on my oponent, rather than just using one end of it... i dont know about you, but i wouldnt think that someone specialist in quarterstaff fighting would weild it the same way anyone would weild a great axe...
I supose it would be something like "Ho! Ha ha! Guard! Turn! Parry! Dodge! Spin! Ha! Thrust! Sproing!"
... that would be nice