Depends on who can afford to purchase or lease it and what The Dulwich Estate, Stonegate and Southwark Council will allow to be built or operate on the site. Whatever it is, it needs to attract footfall for itself and businesses around it.
The question to ask is what does that part of Dulwich need, that is not within the locality, which will attract custom and footfall, that the site can accommodate and that can offer parking which it already has available. In between Cox's Walk, Dulwich Village, Dulwich College and the park, some sort of establishment that sells drinks and meals. Bit then I'm just chucking ideas around, or maybe someone, Dean, has some radical idea's to take it in a totally different direction.
Whatever it becomes it has to be better than the rotting site and eyesore it currently is. Good luck to anyone who takes on the project to redevelop the former Grove Tavern.