Since FSMs seem to make sense in some cases while implementing logic in both the server / database / client it would be interesting to create a language that would be a DSL which outputs transducers (Finite State Transducers) for each part. Using ideas from Functional Reactive Programming would be useful. Adding a schema for data within the transducers would be helpful. You would end up with something like react where logic would be shared and scaffolding could be created after making the server. This could possibly be augmented by CQRS and or Event Sourcing. I think functional programming would help (Clojure or F# would be my choices for implementation). This would also help with vendor lock in.