Probably a sequel to Command & Conquer 2 (Tiberian Sun), but specifically from the writers of C&C 2, or the writers of C&C 1. I'd like to know what would have been their vision of C&C 3. I did actually enjoy C&C 3 Kane's Wrath, however; but the base C&C 3 game was underwhelming (Kane's Wrath was written by different writers than the base game). The interesting thing about this franchise (the mainline C&C games that is, outside of the Red Alerts) is that it was written by different writers for every title. So the continuity was a matter of how well the new writers connected / followed from the previous game's storyline and events.
The writers were as follows:
C&C 1: Eydie Laramore, Ron Smith, Joseph D. Kucan (yes, that's Kane)
C&C 2: Donny Miele, Brett W. Sperry, Erik Yeo (they also wrote for the Firestorm expansion if I'm not mistaken)
C&C 3: Brent Friedman
C&C 3 Kane's Wrath: Samuel Bass, Haris Orkin
My favorites will always be C&C 2, C&C 1 and then Kane's Wrath. But even if I did enjoy Kane's Wrath I still would like to know where the story would have gone without the inclusion of the Scrin. The actual gameplay wasn't bad at all, for either C&C 3 base, or Kane's Wrath. But the story was mostly a matter of interpretation, especially for the base game if the player didn't buy or ever played Kane's Wrath. The main 'problem' with Tiberium Wars' campaign is that it had two endings, and the 'canon' one was essentially your own favorite; and from there you just told the story to yourself. Basically, there was no 'actual story' set in stone. It was up to you to think "Hmmmm, ok I'll take this one and say it's canon".
Then comes Kane's Wrath, which is a sort of 'Flash Back' style story where we start before C&C 3 (or right after C&C 2 Firestorm), and end up with one of the two C&C 3 base game's campaign conclusion, which then one can argue suddenly makes that one ending the canon one. But the problem is that in the end, after Kane's Wrath is over we're back to "square one" so to speak since it did not actually conclude C&C 3's ending at all. It just repeated one of the two you can get. So Kane's Wrath isn't a progression, it's a dead end, and it's still a cliffanger in the end that essentially didn't go anywhere extra. However, in and of itself, I thought that Kane's Wrath was well written. Basically the story telling portion was good (and I thought was significantly better than base C&C 3's).
Now I do say that I'd like to see where the story would have gone to without the Scrin. But the reality is that ever since C&C 1 I (like many, if not the majority of the fanbase who played the campaign) always felt that something was 'off' or mysterious about Kane. And by C&C 2's timeline it was hard to think that Kane was merely just a human. However, I never expected the story to go full blown StarCraft mode with 3 factions, lo and behold the third one being aliens. I DID, however, expect that one day the story would include 'alien stuff'. It might have been the discovery of the alien home system from which the Tiberium-filled asteroids came from, for example. Or it could have been that Kane was in fact a human but perhaps unbeknownst to him he had been experimented on with some top secret military research done on some alien artifacts and Kane escaped and eventually created the Brotherhood of Nod. Or you know, things along the lines concerning his most likely non-Human origins (to some degree anyway).
But a typical sci-fi 'alien invasion' scenario was among the last things I was expecting to be honest. That's probably why in general C&C 3 was considered the weakest of the main trilogy. It felt like it was some sort of a fast-food easy story telling approach to an otherwise potentially more complex setting and world. At least I felt that way. But as I said before I did enjoy Kane's Wrath on its own. It's just when you try to connect it with the previous two main titles it's really rough on the edges. It's better enjoyed as an isolated 'spin-off' type of game than anything else. With all this said, there's C&C 4. I could have said that the sequel I want would be a 'true' C&C 4. But the reality is before we'd get there (in my book) we'd need to get a different take on a real follow up for C&C 2 first. Then we'd see. I wouldn't feel comfortable just keeping C&C 3 + Kane's Wrath as is only to move from there again for another C&C 4 that would most likely include the full fledged Scrin alien invasion of Earth that both C&C 3 and Kane's Wrath allude to. It's too easy and straightforward for a story.