Just remember that adopting DCC will not make your SC-2 controllers work any better 
. It's possible the problem is that they have died or on the way there, rather than an inherent system design and implementation problem. Any recent thunderstorms in your area? Replacement of one of the dysfunctional ones with a new item could be one strategy, or at least testing by a shop that has that capability. Even cheaper and easier is to move the functional SC-2 to the position of the failed devices and see if the switches now work. If they do, the problem is the SC-2s, not the system. Not as expensive as ditching the whole system.
I believe you can get similar devices to the SC-2 for DCC, but have no idea how easy to implement or reliable they are. I believe there is a recent series (last few months) on layout control electronics with DCC in Railroad Model Craftsman that you might want to get hold of.
