DDO is unique in the MMO space. There are some great points of difference. I believe the way for DDO to win is to accentuate those differences even further. Here's some of the things I think DDO is great (and different) for:
--Character progression/customization. Awesome breadth of capabilities for players to try. Practically infinite character progression possibilities. Seemless multi-classing.
--Traps. If you came from any other MMO, the first time you entered a quest with traps you were inspired.
--Unique quests. The quests in DDO are awesome. No two are alike.
The way for DDO to win is simple. Accentuate those positives!
--Fix those character abilities that are gimped or broken. Bluff skill. Sap feat. Restore potions for raging Barbarians. Spells that land behind moving mobs. Fixing things increases the possibilities and customization players enjoy.
--Increase the races/classes. I know this is complex and in the works but it can[t come soon enough.
--Make the traps have some random elements. The first time you saw a DDO trap you were awed. Two billionth time you were yawned. It's not that hard to add some random elements here.
--Add more quests. Obvious and something Turbine seems to understand well.