Not to excuse Disney's lack of investment, but I do think it makes sense to hold off on any new large scale nighttime entertainment for MK (i.e. light parade or fireworks) until new night shows come online at other parks (i.e. RoL and the other DAK stuff, the large SW multi-media show planned for DHS). That way, you don't exacerbate the crowding at MK and park hopping to there at night. I mean, that will happen anyway, but at least having other options open will somewhat lessen it.
Of course, the issue is waiting so long to update/create new shows at the other parks to give a viable alternative for MK in the evening. that's on Disney and their poor planing.
Back to the issue on hand, I think we'll likely at least see replacements for Wishes and MSEP (though I wouldn't be shocked if the "new" parade is PTN coming from California). I'm hoping that we also get at least one new ride -- the OP suggested that Tomorrowland and Frontierland were being looked at, but that might have been put on hold.
Whatever happened to the alleged $350M approved to go to MK anyway as part of the big budget from last summer?
