This is my idea for a Final Fantasy 7 compilation game.
It's called Fantasie's Passing.
Based 10 years after the events of Advent children, Cloud, Vincent, and everyone else have changed drastically. 2 years after the events of Advent Children the Life Stream fell into a comatose state. All Materia, magic, and mako is rendered useless and no more souls can return to the life stream after death, there is only nothingness. Wars and battles break out all over the world.
The 8 years of comatose Life Stream has left the planted virtually dead, and not even the mighty Omega can awaken.
As for our heroes: Cloud has changed over the past 10 years. He has become able to take on any battle he faces and indeed has fought many battles. but there is only so much our hero can do alone. That is why he is not alone. Fighting along side him is his old friend Vincent Valentine.

Vincent Valentine has changed as well, but not for the better. With the life stream comatose, Chaos has ceased to exist within Vincent, and his body can only survive with out him for only so long. The past 8 years have been heavy on Vincent. His body is degrading. Slowly but surly Vincent Valentine will die.

That is, if Cloud and Vincent can work together to reawaken the life stream. All will return as natural, but what exactly caused the life stream to fall comatose in the first place will test Cloud and Vincent in every way to their limits.
(spoiler: It's not Sephiroth although he will play his vital role. I'm thinking of a reanimated Zack Fair controlled by some unnamed organization. That should stir up some drama)

I imagine the game to be like Metal Gear Solid 4, co-op style(online or off), and the options to switch the battle system between a first person(over the shoulder like Dead Space or Resident Evil 5) shooter, hand to hand combat, and sword play similar to Ninja Gaiden.
The game play should have alot of options, and the replay should be different based on what path through areas you take. Multiple alternate endings and in-game scenes will be available. lots of unlockable game modifications such as, alternate costumes playable characters and super weapons included.

Cloud and Vincent look different don't they?
I wanted to make a realistic believable story plot and characters. Cutting Cloud's hair solves the anti-gravity syndrome and making him buffer should give excuse to why he's so strong (don't give me that mako injection BS, Cloud was pewny in Advent Children and you know it)

Their costumes are based off their outfits from Advent children just much less outrageous. Getting rid of Cloud's mini skirt, one sleeve, and straps all over. vincent's gold bling and cape(replaced with a torn red trench coat). The outfits look more believable now at least I think and a little more bad ass. But if you like the classic costumes such as their costumes in Advent Children and FF7. Then they will be available in alternate costumes.
Notice the cirus vests Cloud and Vincent wear. I'm really putting emphasis on the war and guns aspect of the game and story. Final Fantasy almost never includes firearms, at least not properly(except for Dirge of Cerberus). In shooter mode there will be a wide range of hand guns, rifles, machine guns, shot guns, rocket launchers grenade launchers, etc. As well as customisable parts.
In hand to hand mode there will be a wide range of Martel arts moves and close quarters combat to make the game into one big brawl if you want. But some points in the game will make it impossible to proceed with just your fists and feet as weapons, no duh.
In sword play mode, well just think of Ninja Gaiden including all of Cloud's old moves and allot more moves to do. I'm sure you be able to deflect a bullet or two if you use your blades wisely and by blades i mean, combat knife and machete. The buster sword and Tsurugi will only be unlockable super weapons, sense they are so unrealistically huge and Cloud would most likely move like pyramid head with it in real life. Vincent's Cerberus gun will also only be an unlockable super weapon.

Well that's pretty much it. A cool game idea but only an idea. Exclusively for the PlayStation3
All characters and copy rites belong to SquareEnix, bla bla bla.