Two changes to the current game would make this more appealing.
1. outline of what classes get at each level. A lot of people want this anyway. But until we get that, there is no reason to make respecing so expensive
2. Allow spell changes without respeccing. Yeah, I get that's not how it works in D&D, but it's painfully stupid to have to do a full respec to change a single spell. Many don't even want a full respec because you have to remember every other spell/ability/feat you picked to change one skill.
The problem with point 2 is that it's a major defining feature between wizards and sorcerors.
Arcane casters in Larian's system are nerfed in various ways, but that applies to both sorcs and wizards. Wizards, however, are even further nerfed in COMPARISON to sorcs by several factors:
1. First, just the fact that a bunch of spells simply aren't implemented. That makes the wizard's advantage of spell diversity less valuable.
2. Second, the fact that this is a computer game and therefore inherently much more combat-focused. A big advantage wizards have over sorcs is just how much utility they bring to the table. In BG3 they miss out on that because BG3 is *nowhere near* as flexible as a tabletop session.
3. Everyone can use scrolls; aka anyone can access the wizard's main strength, *spellcasting diversity.* This dilutes both the sorceror and the wizard's uniqueness, but it hits the wizard far more.
4. The current ease of sorceror respeccing is ALREADY a humongous buff to them. They can essentially (especially at higher levels where the cost becomes trivial) swap out their spell set at will. The only difference between wizard and sorceror right now is really that it's a bit more of a nuisance for the sorceror.
5. For some reason, Larian decided to grant sorcerors their 14th level special abilities at 12th level, while not really making any equivalent exchange for wizards.
In other words, due to a combination of the limits of video games and some (poor, imo) homebrew decisions on Larian's part, the advantage that wizards hold over sorcerors is already paper thin; letting them swap out spells without even the nuisance of a respec would destroy it entirely.
However, I hear your pain. I never liked the system sorcerors had, personally, where if they were a newer player just not as familiar with the effectiveness of certain spells, they were essentially locked into the same spell set until they leveled (and even then could only swap out 1.) I think there can be a solution.
First: Give sorcerors some LIMITED daily ability to swap out spells. Once per long rest, they can swap out a single spell. This would allow them a limited ability to ditch bad spells without going through the nuisance of a full respec.
However, this doesn't change the problem that a respec is cheap and easy, still, and essentially means that sorcerors can have the exact same flexibility as wizards, just with a little more effort (trivial gold exchange and however long it takes to load camp.)
So I think that something easy that can be given to wizards is: they just have access to MORE spells than sorcerors. TO a degree, this is already true. Not every spell on the wizard list is on the sorceror list. And there are already some scroll-only spells in act 3, with wizards the only ones able to copy those down for repeated use. But give them some more, and have them in every act. They don't have to be crazy, either. How about a version of fireball that does radiant damage instead of fire? Potentially useful in certain situations. Larian could even take a look at implementing some version of the OneDND spell creation system that allows wizards to create personalized versions of their spells. But even if they don't, I think sprinkling in some scroll-only versions of spells, that only wizards could cast multiple times, would help give them something unique in comparison to sorcerors. I wouldn't mind them keeping the cheap respec, then.
