THIS IS MY OPINION THIS IS NOT TRUE (yet hopefully).

they could add Sai and Yamato(and 4 tailed naruto...why not) all the way up to the battle with Orochimaru. Theyconfirmed that Saske retreival arc would'nt be in CoNR but this is(i think) a filler so whoknows. Tomysays they have a surprise so this would be cool.

Like i said this is my opinion.

Comment if you think they should do this also if i find any more info i'll update see ya;)