That's a 6e discussion. Cutting and elevating some subclasses and toning down some classes.You're not going to find a lot of consensus here. Half the community wants bland flavorless piles of mechanics they can describe however they want and the other wants a separate unique class for swashbucklers, knights, samurai, gladiators, gishes, etc.
Part of the design issue is that the fighter alone doesn't mean anything: a fighter represents any adventurer who can swing a sword. The wizard represents a specific type of person: someone who learned a specific type of magic via a specific method. And too many people want the fighter to be that generic "fill in the blank" class for them to change it.
But when it comes to 5e and the wizard itself as a class and possibly the Warlock and cleric..
We might need to have a discussion about
Subclass specific spells.
Because really there's certain things that people want to be able to have in some classes that really require a specific spell handcrafted around that specific experience that is not available to the base class.
If you want some ultraspecific fire spell or effect, it might require taking that specific fire based subclass which locks you out of access to other Elemental spells. And that's spelled might not fit on any main class at all.