I would like to see better "niche protection." Which isn't the same as a nerf.
Why shouldn't the rogue have Knock, or at least an ability that works with the same reliability and skill? And why shouldn't they have a Spider Climb equivalent? And why does a wizard get it? A wizard should generally not be climbing around and opening things, right?
Narrative control like that is powerful, and I'd like to see it given to the classes that are supposed to be in control in a given situation. A bog-standard wizard should not be in control when stealthily exploring the ruins. The rogue should. The wizard should be in control when the party finds a tome of ancient lore, or a strange green liquid in the pools outside the shrine to Juiblex.
Well how how about protecting the wizard niche? A rogue at high levels who has poured ranks into use magic device can very effectively compete with a wizard in the spell category. Not only can he use arcane spells but he can also use divine spells.
The rogue also with his back stab can compete with the fighter when it comes to doing damage in combat.
Then there is the cleric with his buff spells and access to heavy armor he can more than compete with the fighter to be the frontline tank.
It is almost impossible to totally protect niches there will always be some overlap.
As for the spells you mentioned like spider climb it is should be in the wizard repertoire. Wizards are not as strong as fighters and they don't have climb as a skill so they need to be able to climb that cliff face. They can also use it to help other classes.
That is one thing I have noticed in these conversations is that no one seems to be talking about the wizard casting spells on the other party members to help make them more effective.
I play a wizard and I routinely cast invisibility on the party rogue to help him scout better and more safely.
As for knock sure as the party wizard I could memorize this spell and use it to open doors. But unlike the rogue's pick lock ability I am limited on just how many spells I get so eventually I won't be able to do it any longer. A rogue can open locks and disarm traps all day long. And that ability does not stop him from using his other abilities. He can still use his back stab in combat and evasion to avoid damage.
A wizard who has taken a lot of knock spells has to to that at cost of taking other spells that will help protect them and help them fight in combat.
Another reason spells like knock exist is to allow the party to be able to function without a rogue.
I rarely see complaints that bards and druids getting healing. Though healing is supposed to be in the purview of the clerics. But design wise they get healing so that a party can survive without a cleric.
It stops the "we have to have this class or else we can't play" and allows more flexibility to the players.
I keep reading that wizards step on a lot of feet but in 20 years of playing the game I have never seen this at the table. I have never seen a wizard character that takes spells to be better than another character in the group. Why would a wizard take a lot of knock spells if the party has a rogue? By doing so they limit what they can do and that is not usually fun.
What I have seen is that wizards may take a spell to help boast or back up another character that is not stepping on toes that is called being a team player and helping make the party as a whole effective.