Based on the fantastic season 3 premiere, this is what I'm guessing we could have gotten in the first half of season 3 if it had a full season:
The Witch gang adjusting to life on earth
Uncovering the location of the titan blood would have been stretched out through multiple episodes
More bonding between the Hex Squad and Camilla (and Vee)
Vee having to adjust to basically starting all over again with a new persona since Luz is back home
MORE HUNTLOW MOMENTS 😭😭😭😭😭
Seeing Hunter and Gus be total bros
Seeing Luz struggle to adjust to life back on earth, especially at school
Delving even more into Camilla and Luz complicated relationship
Hunter being corrupted by Belos would be a slow burn as he starts acting differently the more Belos takes control