I think it's important to say right up front that even in a new engine we'd be looking to bring many of the core content items forward - there's been a lot of great work done over the past years (decades?) by BG devs and the community in areas like the unit database, regional information, map details, events, etc.
Some things will by their nature be a bit tricky - for example, how can you progress from a 1936 (or 1914) map to a modern map smoothly but historically accurate to reflect population redistribution, new urban development, transportation, etc. Not sure if we can actually overcome that particular problem easily, there will always be some tradeoffs. But with regard to things like our Equipment list, which even with its flaws is I think the best and most detailed database of its kind out there, we want to certainly just build on and improve it.
We also want to keep game datasets and structures familiar to players and modders. So we may add new data elements, and increased limits, but don't expect the regions CVP file to go away, etc.
-- George.