They absolutely could do it.

Can someone explain why Sindel's hair moves are so hard for a console to perform?

I understand Shang's morphing is intensive but what's so bad about the hair?

Nothing. People ASSUME there must be something difficult about it just because the hair grab move wasn't in Deception. But that wasn't difficulty, that was laziness. Lots of moves got left out of DA and Deception.
Like I said in the "Technical Limitations" thread, graphically, it's exactly the same as putting Scorpion's spear into the game.

i agree as i learned 3D animation its totally possible to animate something to stretch and become larger even bend like a tentacle, look at resident evil 4 when saddler transformed into that giant monster you saw giant limbs grow right out of his head and this was in game graphics, i agree in deception it was probably due to time constraints or laziness considering they were probably using the basic human skeleton rig for all characters. here they could have added bone rigs to her hair so they could be animated to stretch out and wrap around the opponent, another trick since her hair is big they could hide a bunch of tentacles in her hair (give them hair texture) and have them come out of her hair and wrap around the opponent, hell if they can animate jereks rope grapple in Armageddon they can easily pull this off especially with WB's resources and animators they have its not just the same MK team its the MK team and the Wb working on this game

I feel like they will give her a hair move but the hair won't extend.

My guess its the game reason that we dont see much of Tom and Jerry physics in 3D animation/games. Because it doesn't look good unless you really put the time into it.

Sindel's hair moves didn't look great in MK3 anyway.

But they should be in this game.

well if bayonetta can do it ;)