Months ago has been rumored a Playstation allstars sequel would be announce at E3 of 2014 but, they turned into to fake.

the "leaked" image:

"Like to see us comeback to the idea, but "not the same mechanic".

Shuei Yoshida Sony Playstation worldwide CEO

The first PSAS many issues like, roster, lack of content, the same song every character trailer, online problems, glitch "called as Super Smash Bros ripoff" etc.

_{Side note: i'd did not play PSASBR}

Sequel improvements:

Character Soundtracks:

All trailers in PSASBR the same song over and over ugh! For the next sequel put character main theme would'be amazing to see because, fans would'be recognize those amazing memorable soundtracks.

More modes:

Story mode

Tag-team mode

Challenge Accepted (similar to MK9 challenge tower)

Endless Battle

2D Mode (attract both old and new players.)

Arcade Mode (fix some problems here)

Classic Arcade Mode (like the old fighting games with bonus stage)

Improved character roster:

A lot people characters like, Crash, Spyro, Sora, Cloud, Solid Snake, Lara Croft, Dart and Abe according to fans are most highed anticitiped characters. Add some reps for well known franchises and scrap some characters. Balancing between ps1 to ps4 era.

Give the game to proper developer:

That Playstation allstars should be developed by a company who more experience in fighting games over the years.

Also co-development is more helpful it's feel more like "partnership" between two companies in one. "The union make a force."

Exp like: Santa Monica Studio and co-developed by Netherrealm Studios or Santa Monica Studio and co-developed by Cyberconnet2

Better name choice:

Instead of "Battle Royale", let me show you some better names for Playstation allstars examples: Playstation allstars: Rising, Playstation allstars: Omega, Playstation allstars: Alpha or Playstation allstars: Legends or Playstation allstars: Legion.

Sorry my English is not pretty good
Some Suggestions let me know in the comments