I think the answer is WAR!!! We need a really great war in Hyrule... and a really really long zelda game... let's say minimum with no side quest 60hrs... The game would be something like this...
I would start right after TP... as we know after finishing TP ganon is not dead... in fact... he allied with the neighbouring kingdom and along with the gerudo, he is planning on invading the land of hyrule... zelda ask link is he could gather and army to defend hyrule...
Here starts part 1 of the game where you have to ask the gorons, the zoras maybe add some races from past zeldas... to join you... obviously you will have to complete certain task and all that zelda-like things that we love... certain side-quests will enable you to obtain specific weapons to use on the battlefield like catapults or an experimental bo-bomb cannon...
After you obtain an army that you like you go and talk to zelda to inform her that the army is ready... now is when a different zelda starts... You will command the army... and you have to divide you troops in different squads in order to defend the different regions around hyrule... here is where depending on you strategy it would be easier or harder to win an specific battle... you would fight in lake hylia... the gerudo dessert... kokiri forest... goron mountain... and finally hyrule field... ( you would go from each battlefield to the other by riding on epona or maybe using some kind of item )
After the final battle in hyrule field anything could happen in other to expand the game... like link is killed and then he pulls a "God of War II ressurrection" or anything... i don't know..







