Whoever buys EDI will invest, and will do all they can to attract much needed long-haul business. IMHO no one would pay for an airport, only to leave it alone and NOT inviest.
For a captal city, financial centre (albeit much reduced in status over recent years) and tourist gateway - EDI needs to be much bigger and better at what it does...
There will be ongoing development of the SE Pier, creeping even nearer the Business Aviation Terminal but a further revamp of the area between Gates 5 down to 1 needs urgent attention, as well as an expansion of the arrivals hall below
Lets see firstly, who buys EDI and then their plans