This might be the fastest I've ever homebrewed something, but here is my take on the Witch coming out in a few days.
Personal Opinion:
The Witch as printed is severely lacking, and is unnecessarily constrained. Instead of "pick a list" it's "pick a list/hex cantrip". It also leans too heavily into the patron and familiar, which were always side dishes to the main course for me: hexes.
Mechanically, the class is too weak, so this class archetype is a sizable increase in absolute power.
Furthermore, I always felt that the class's key ability score of Intelligence indicated a certain amount of independence/ambition that the current Patron dynamic wholly undercuts.
Goals:
1. Give more cantrip hexes
2. Increase class's absolute power
3. Give a better option for a buffing cantrip hex
4. Give more flexibility in character concepts
5. Reduce dependence on Patron
6. Reduce significance of the Familiar
Approach:
I removed Patron as a class feature, replacing it with Magical Affinity which is simply the "Pick a List" feature.
Patron themes are gone, and the bonus spell known granted by them is also gone.
I made the 1st level cantrip hex a free pick from the list.
I added the cantrip hex "Inspiration" which is a single target Inspire Courage, with hex limitations. If this is overpowered, then a. come at me bro and b. Inspire Courage should be fixed.
I removed the built-in Familiar Ability increases at 6, 12, and 18, replacing them with extra cantrip hexes known. (Absolute power increase, since hexes known is better than familiar abilities)
I added a new Level 2 feat that lets you pick out an additional cantrip hex.