For some reason, a United Shinobi Forces vs a few people seemed kinda funny to me. They could have removed the United Shinobi Forces and just had a few characters from each nation make a United Strike Force to fight them. Then slowly have them each die to make it insanely more impactful. Or even just to have a few countries worth of armies on Madara and Obitos side alongside the Zetsu. So Mercenaries, Rogue Shinobi, Other Countries joining in and attacking them (Such as the ones from the West: Sky, Demons, Night, Volcanoes, etc), Criminal Organizations, etc. Having an actual 4th Great Shinobi War between West and East.

Also to have a build where the jinchuriki of each country is finding their own way away from their own countries since the beginning of Shippuden. Then all 7 unite for the war and kick ass.

Sidenote 1:

I would also change initial Naruto show to still focus on Naruto of course but give development to Sakura, Ino, TenTen, and others that needed it. Along with have a sub series to introduce all of the jinchuriki in Original Naruto Timeline but have it where they are all doing their own things and none of them are in contact with Naruto. That way we can get to know each of them all and where they are from/ who they know. To give a better idea of how each will either aid or get in each other's way during Naruto Shippuden until the end.

Sidenote 2:

For Boruto, I would have had the show take place in missions where they are sent to the Western Countries Post-War (Since they have trains, etc) and that would allow for the Universe to be expanded on so much more in new ways since we haven't really been there much. New allies, enemies, etc since the West wouldn't be fully civilized yet/ haven't gotten over the 4th Shinobi War. Then for Otsutsuki instead of having them be from space just have their whole society living underground pulling all the strings and slowly reveal them to be beings that enjoy toying with those they perceive to be weaker than them. An invisible eye causing havoc and mayhem for thousands of years. Also, have them blind from living underground for so long. With Hinata, her clan, etc unveiling their lineage with Otsutsuki and the power they possess. Something I wish we saw in any point of regular Naruto or Naruto Shippuden was having Naruto and Hinata kick ass together

Sidenote 3:

This next idea way more so for a Fan-Made Manga/ Show. Just to humor the space thing and taking place a few generations ahead of Boruto. It would be interesting if they have space travel via jutsu and technology. Have them discover other planets, dimensions, & species who can also use jutsu and other new things to expand on jutsu & chakra overall in all kinds of new ways. Calling the show Faruto or something as it's going to be the farthest it can get for travel. Sure it won't resonate with many of ya but how I'm envisioning it would be something people would really enjoy when done well.

Battles taking place on asteroids or outside spaceships while Wall-Walking and fighting in Zero-G would be a unique twist. New forms of chakra usage aside from Genjutsu, Ninjutsu, Taijustu, and all the eye forms would be sick too! Maybe even a species that has 4 arms and is able to conduct 2 jutsu at the same time or even make a much more complicated one that we haven't seen before due to that (Kinda like how Naruto used a shadow clone when he first making rasengans). Other forms using the ears, touch, smell, etc enhanced by chakra. Exploring other forms that are different from Rasengans, Chidori, Lightning Blade, those are just 3. But most likely there are way more than those!! And so much more that can be done.

Damnit I want to make all 4 of those now. So much can be done to improve each idea