How would you rewrite Mulan 2?
I'd just begin from scratch really. I tried to come up what would I keep from the existing sequel and I think that's maybe just the yin-yang necklaces. Which were a deleted idea from the first movie anyway.
Easy and lazy answer would be to go with whatever idea they had in Mulan 2's deleted scene, battle sequence, (check it out, it's super cool). It's like spy-ninja-duo of Mulan and Shang working like a badass couple. Mulan 2 concept arts (part 1, part 2) are not too bad either, and although they definitely have some usual Disney sequel cliches(eg. having the girl Mushu dragon), I'd still think I could enjoy it a bit more than what they ended up with.
Then there's Barry Cook's draft, aka the co-director of the original movie wrote synopsis for the potential sequel when he heard that Disney was considering of doing sequel to Mulan. In fact there was going to be Mulan 3 as well, apparently Mulan 2 ruined it as it was too badly received. There's hardly anything known of Barry Cook's draft details, just that soon-to-be-married Mulan and Shang are sent to north since things are happening there, and at the end there would have been an epic battle between Mulan's ancestors and Shan Yu's deceased army.
Actually I lied earlier what would be easiest and laziest. That would be just doing the visual novel The Palace of Secrets. Seriously I wouldn't change a thing.
There's many directions where one could go with the sequel really, some fanfics have done pretty amazing job exploring different options. I have made a post where I put up some fanfic recommendations, but some are like one-shots so they could hardly be sequels.
Personally, rather than a sequel movie I really really would like to see Mulan tv-series. Something like Tangled: the Series. It could have the sillier filler episodes but the main plot could be epic. Series could also make possible to explore side characters' character arc in more detail. I have played with this idea before too, with my friend @mulanxiaojie.
I'm quite satisfield how the first movie ended, but I'll list some pointers that I and I think most would like to see in a continuation story:
Mulan and Shang getting together
And then some that are not really necessary but would be really interesting to see, just to list some of the potential sequel tv series could have:
Mulan's and Granma Fa's relationship
seeing the other guardians besides Mushu (and the Great Stone Dragon)
developing Gang of Three as invidual characters
exploring historical China
an actual villain (should be basic but the sequel didn't have that)
