-bloody palace co-op
-playing any level with any character (after completing the intended campaign once)
-playing any level (except boss only levels) in co-op (after completing the campaign once)
-Turbo Mode
-Legendary Dark Knigth
-Must Style Mode
-Floor is Lava (when entering combat the ground turn red and does small continous damage, but doesn't penalise style)
-all 4 modes above are check boxes that can be all enabled/disabled at the same time before every level; but Legendary Dark Knigth couldn't be used in Bloody Palace (for obvious reasons)
-Vergil DLC; complete with his own campaign, where he and Dante get out of hell (let's say 7/9 levels, the first one about figthing Dante and the last one battling Nero and remaining ones would be co-op)
-Lady & Trish DLC; some 3 levels would be enough; the first once could be mission 10, that Trish way could have Sparda before switching to a new sword; all levels would obviously be co-op
-a 2 level campgain DLC about Dante's figth with Balrog (which is set in the DMC2 levels); that way they could introduce Lucia and redeem a bit of DMC2 (plus I think the island's of that game is neat)
-a 2/3 level DLC based of the current V manga, which is set rigth after Vergil seperates his humanity (he figths Phantom in that manga)
-"Clean Up Duty"; a 2/3 level DLC where Nero must deal with the aftermath of the Demon Tree; we get 1/2 new Devil Breakers
-after all these campaigns are cleared we get a cutscene with a conclusive ending to the Sons of Sparda
-finally a DLC about enemies and bosses of the entire series; where 2 bosses and 3 regular enemies from each game before 5 are introduced; the regular enemies could appear in the previous DLC's and even some in the main campaign
-a Boss Rush game mode, where the player figths all bosses from 5 (except the plant) plus the ones that are introduced; the player only has one life and a handfull (if none) of green orbs
-DMD Bloody Palace; similiar to the one in DMC3; 1001 floors with the choice of advancing 1 foor for health, 5 for DT, 10 for nothing; in this BP would have much more enemies per level (so co-op could be properly challenging) and have all enemies and bosses (and shadow and griffon wouldn't be bossess)
-8/9 more secret missions (spread across the DLC's)
-more costumes; with specific requeriements to be unlocked (like in mission 18 Dante must land on Shadow's spear to unlock the DMC1 costume); one cool costume for Dante would be El Donte, where all of Dante's lines would be replaced with unique spanish lines, the style announcer would obviously be spanish, Faust Hat would become a sombrero and Dante would get a mustache, and etc...
-up Sparda's damage and give it a unique moveset that makes use of the sword's transformation capabilities; DSD base damage is also increased to match Sparda's
-give Drive to Rebellion
-2/3 new moves for V
-more counter buster's to Nero (I think that's the only aspect where Nero is weaker in 5 than in 4)
-Pandora, Lucifer, Nevan, Agni & Rudra and a combination between Artemis+Nightmare for Dante; Nevan would be a gun
-being able to actually listen to music in the Gallery
-more battle tracks to switch on the PC's; boss themes unlockable as battle themes
-make SoS enemies more aggressive; decrease enemy HP in DMD and increase their damage
-give Vergil a DT (not SDT), he would start using DT after losing 1/3 of HP and uses SDT when he only had 1/3 (1/4 in lower difficulties); give him 1/2 more special powers in SDT, like the time slowing abilty; make him mix up a bit more his attacks (so instead of always following attack A with attack B, he would use attack C); if they make Vergil playable and give him more weapons (such as fists or other Devil Arms), then once the player aquires those Vergil's boss figth is updated for him to include those weapons; when figthing Vergil with Nero, those moments where Vergil is "tired" (taking a knee for Nero's Buster move) should only last at most 3 seconds;
-also reduce amount of gold orbs given to be player and better yet and make an option to sell them in the shop (1000 red orbs for each gold one seems a good price)