I think if turbine was smart they would make an epic house in the game. It could have have different portals for every 5 lvls ie, portal 1 would have all lvl 1-5 quests in epic lvl only ,6-10, 11-15, 16-20. I understand something like that would be huge to try and put into the game as an update, so why not build it into an actual expansion pack? That way those who enjoy the non-epic ddo can continue on with what they want to play and those that want epic gameplay can buy the expansion pack for X amount of dollars.
It would work in the same way as titan quest does. You install the expansion then copy any lvl 20 toons from reg ddo to the expansion pack. I'm sure this might take some time to do of course but in my opinion that would be a winwin all around.