Stargate SG-1, without a doubt.
Despite not liking the way they handled Sha’re’s death, I still liked the show up until Season 6. However, things started becoming really bad after they made Daniel Jackson become an Ascended being. The reveal that the Ancients and the Ascended beings are the same thing, the introduction of the Ori and the death of certain characters are all things that I would have avoided if I was in charge of the show.

So, these are my ideas to rewrite the show:

The 1994 movie and almost everything from the first 6 Seasons of the show remain intact.
The Ancients and the Ascended beings are two different things. Like in DuracelEnergizer’s Divergent Universe, the Ancients are revealed to be Reptilian humanoids. Millions of years earlier, they created a great Empire that included the Milky Way, Andromeda and the Triangulum Galaxy. However, at some point their civilization collapsed, which lead to their extinction. As for the Ascended beings, they’re not a prehistoric species of super-humans, but just people who reached illumination, and they can belong to different species.
Daniel Jackson does not become an Ascended being and stays alive until the end. Therefore there’s no Jonas Quinn. Not that I hate the character (I quite liked him actually), but let’s be honest, he was just conceived to be Daniel’s replacement, so we can do without him.
General Hammond leaves the Stargate Command like in the actual show, and Jack O’Neill becomes the head of the Stargate Command. However, he remains the head of the Command until the end, so General Landry does not exist. Cameron Mitchell still exists and serves as replacement for O’Neill in the SG-1 team, though.
Anubis’s backstory doesn’t change, but everything would be adapted to the changes I’ve made to the Ancients and the Ascended beings. So, most of the Anubis arc would remain intact, but he would be definitely defeated over Antarctica thanks to the use of a super-weapon created by the Ancients during their reign, which was brought to Earth by the Stargate Command itself.
Everything we know about the Replicators would remain the same. After the defeat of Anubis, the Stargate Command would defeat the Replicators.
Vala Maldoran would be introduced a bit earlier. Specifically, she would be introduced after the defeat of the Replicators. Her personality doesn’t change at all, and she would eventually become another member of the SG1 team, like in the actual show.
Like in the actual show, during the Replicator invasion of the Milky Way the Go’auld Empire lost a lot of power. The Jaffa become an independent power. However, Ba’al becomes a sort of Thrawn-like figure who tries to rebuild the Empire, but the Stargate Command and the SG-1 would eventually defeat him. After the defeat of the remnant of the Goa’udd Empire lead by Ba’al, the show ends with the Asgard giving the Humans all their technology, with the total disclosure of the Stargate Program and with the Humans becoming a tru interstellar power.

That’s all.