Lower fees for a larger amount of time would pay people back over time after a while. I'd imagine you have a list of the addresses who had unsubmitted shares during this time. You could even just do it for them as a kind of loyalty thing to get them back on board?

I'm just speaking for myself here, but i'd be back on board with my 3.5mh if you did this. If i'm willing to, then i'm sure others would be also, if thats the case over the long term i'm sure it would make you more and you'd probably gain more mining share than the ~1mh/s that were mining on your pool before this happened.

Cheers!