I think Activison would make great job if they make old Crash series to ps4. I like new Crash, but old ones were much better. I hope so Activision will look at this. There are lot of funs of old series such as: Crash: mind over mutants and Crash of the titants.
I honestly think it would be a great idea to have Wrath of Cortex remade for the New Nintendo 3DS and New Nintendo 2DS XL, while the N. Sane Trilogy gets a few DLC levels from Wrath of Cortex added to Crash 3: Warped's new warp room chamber with newly redesigned levels from Wrath of Cortex. Considering the Time Travel theme from the game, four new levels featuring Wrath of Cortex content isn't out of the question.
A remix of Knight Time/The Gauntlet (which are alternate versions of each other from Wrath of Cortex) prehaps Wizards and Lizards, Bonzai Bonsai, Gold Rush, Jungle Rumble and Compactor Reactor are my choice favorites, Gold Rush being a must see level in the series, being Wild West themed, it fits in with the whole time travel theme.
and lastly, after you beat all five levels in that Warped room, a brand new boss level should appear. Maybe N. Tropy's loyal sidekick brings back a boss fight from the future?