Let me give you my user experience and see if you can help us play your game more:
About seven of us played a game of Blight of the Immortals in turn-based mode, namely because we all have jobs and would be unable to get to the devices appropriately. The turn-based functionality is an add-on that causes immense game issues where characters can be held for long periods of time in stun spells, sometimes because of recharge rates and other items indefinitely.
That being said, we love the game, just the quirks of having the turn base sit on top of the real-time throws some wrenches in.
The items for you to take this up a notch are the following:
1. Update things from time to time to make it newer-ish. The game does not feel like it has changed any of the times that we have played it over the four years (has it been that long)
2. Turn based for the die-hard workers.
3. Figure out the Iron Key for paying to play for a period of time. That really worked out for getting us to have one person pay for a key and then we could all play. If a person wants to get new friends to start a separate game, then you have an in for a new key purchase.
4. Ask your users, send an e-mail out to everybody and ask them what their issues are. Ask those that love it to post on their facebook / twitter / etc.