If it were me... I'd probably go the exact opposite way.
I feel like the demographics are too different to make a mascot fighter in the vein of a Smash brothers to work. Which is the kind of artstyle you'd need to make Crash and Kratos look like they belong together.
Were it me, i'd focus soley on the more realistic humanoid characters. Kratos, Nathan Drake, Lara Croft etc.
Make it less Smash brothers, more DC vs Mortal Kombat.
Hell bring the Ed Boon and those guys in and have them do it!
Make a cohesive (well for this kind of game) gritty story like the latest versions with various realistic playstation mascots banding together and fighting moves that allow the characters to look more brutal, and be a spectacle. (Like Injustice)
I feel like that would have a better chance to hit with the target demo.
