We need hybrid support for some occults
I think hybrid support is feasible and would make the gameplay experience not only more interesting, it would also tap into the potential of one of The Sims 4's greatest strengths, its occults are the best in the franchise and having hybrid support would boost sales and make a more unique gameplay experience for everyone, especially those interested in making Super Sims.
They could make a new separate tab for each of the occult ability trees, this has been proven to be possible with Ghosts in Life & Death, they can make a new tab where all of the occult ability trees are listed (Spellcaster Fairy Ghosts for example could have their three ability trees listed in that tab).
They could also optimise the needs menu to not look wonky and accomodate all of the possible needs.
If it really is too difficult to implement wholesale hybrid support, then at the very least allow spellcasters to mesh with one other hybrid since I think one of the bigger problems is having multiple occults with occult forms messing stuff up and making sims buggy. There is a hybrid mod at the moment but not everyone can access mods.