Suggestion: Reintroduce interfaces for field types

[Kern Herskind Nightingale]

If you are to stand up types with DI at any point we probably have to do this.

I realise that this was pulled in order to have operator override support.

Could the same not be achieved with methods like Equals?

[Jason Bert]

Not sure why I've left this open for so long, we're back to using interfaces on the field types :).