I think this stems from min-maxing racial armor proficiency, Wizards being able to learn spells outside of their spell list, and yeah, the Headband of Intellect that allows for choosing Intelligence as a dump stat.
However, I still think most of the classes and subclasses have practical value. Light Domain Cleric offers the best AoE in the game while we're limited to 4th level. Rangers and Rogues offer great versatility in skills, given the main character is typically the one making all of the dialogue skill checks. Warlocks have great versatility in invocations, with the Beast Speech invocation being fairly noteworthy.
Sidenote, everyone chooses the ASI/Feat at 4th level (not 3rd), but even then, a Wizard can't replicate the Agonizing Blast Eldritch Blast damage output a pure Warlock can. If Larian allows multiclassing, then that might change, sure, but depending on the future power of 3rd and 4th level spells, that might put more value in focusing on one class. I will say that using the Warped Headband of Intellect to combo with Magic Initiate Wizard is pretty strong, but thats viable metagaming (if you did this on an actual tabletop session that'd be bad faith).
