Sure there are things that I would've wanted but why can't we just appreciate the things we have now instead of worrying about the things that didn't make it??
Well if i HAD to say something it would be more characters and the Ice Cavern.

I would've liked to see a larger krypt with things that just cost tons of koins, cause in my opinion things that cost lots of koins is harder to get then finding a treasure chest in Konquest because guides tell you where those are at, it's harder to earn than find.
I also would've liked to see Shang Tsung and Quan Chi, mostly Shang Tsung though but not in that goofy alternate outfit, just when he gets a cool look after all those retarded looking outfits they give him that stupid alternate one from DA

well i love the game how it is now but I would have likes to have seen some specials integrated into combos more. not where you even had to press the buttons or they did extra damage but mainly for eye candy.
think about scorpion:
he punches punches uppercuts kicks kicks
in mine it would be punches punches uppercuts (uses harpoon to bring back down instead of one of the kicks but for same damage) and kicks.
it woulda just looked alot cooler. also It woulda been more fun to have had more things to do in konquest than just fight like mini-mini games

"kreate a kombatant"

create a kombatant is like shujinko.......but yeah, that would own

Kung Lao. That's it. I just want to play as Kung Lao.

To all of you who want shang tsung and kano and kitana and quan chi....go play deadly alliance.. this is deception. Kung lao is the only one who is unique... As for the people i want.. Rain would have been nice. But they gave his sweet lightning move to that pansy nightwolf. Reptile would have been cool too. But only in his ninja outfit.

A way to fight on the first pit in background of the pit, in 2D with the 3D models.
Living Forest deathtrap, 3 alternate costumes, intestines for Kenshi's hara-kiri, more special moves for Hotaru, flying move for Sindel, trident spear for Smoke.
Sektor and Fujin.

For you to be able to actually customize Shujinko, with three Fighting Styles that you choose, and decorative objects, like Ed said you could back when Deception's Konquest Mode was first announced.

Kung Lao. And a way to run forward.

More different alternate costumes, because many don't look really different from the first one. Then i would love to have back the animality, babality and the brutality.
And even many more fighting arenas and fighters.
PS: Sorry about my english, i'm from germany :)