There’s another aspect of that debate that should be considered, but I haven’t seen it yet in the discussion:
No, not character classes. Social classes.
To become a wizard, one needs lengthy and costly studies. The wizard’s starting age is one of the highest, and just the most vital tool of their trade, the spellbook, is pricey, not to mention all the other costs of learning.
A wizard needs to be well-educated from the start, and certainly have no time for any other “honest” work during his or her studies. Whether you become a wizard through apprenticeship with a more experienced master, or some wizarding schools exists, it is certainly something reserved for the upper crusts.
An exceptionnaly intelligent individual coming from a lower income background might become a wizard, but only if he receives some sponsoring, or have extremely dedicated parents ready to sacrifice a lot for their child’s sake. Most often, he or she will rather be oriented toward some more immediately lucrative job.
This means that a majority of wizards will come from the wealthy portions of society. By contrast, sorcerers can appear within every social class. They can perfectly come from a “two-horse town” just like Xykon. All they need is the proper ancestry. It doesn’t matter that their parents were just peasants or craftsmen, and that they were expected to take over the family’s craft; their powers manifest naturally, and at a much younger age than wizards.
Sure, you can have the occasional sorcerer born from a wealthy family too, but they are more the exception than the norm. (Those are, IMO, the more likely to becomes Ultimate Magus anyway.)
Even as they rise in power, wizards are more expected to serve nobilities or royalties as counselors. Their trade being extremely costly, they favor having a wealthy patron.
Though sorcerors may vary widely, those that aren’t chased away from their modest communities are most likely to stay on the fringe of it as a local witchdoctor or potion maker, a bit feared by their peers but called upon when the people need some magical help.
Hence the wizard/sorcerer opposition is likely to double as a social clash between classes. Wizards are elitists not just because of their powers, but also from the natural snobbery of their birth. Sorcerers are more lickely to be country hicks or from the unwashed masses. This certainly will add some fuel to the issue.