I disagree entirely. If we were deleting classes based on not having interesting mechanics, then Barbarian and Bard wouldn't have made it past 1E and Monk wouldn't have lasted past 3E, but those are three absolute mainstays of the game at this point that you can't just sub-class away.
The game not managing to express a class mechanically well in one edition isn't justification for removing its fluff potential and shoving it in another class, none of which hit anything approaching the themes of the sorcerer. Sorcerer was mechanically fine in 4E, and its fluff is still absolutely strong enough to justify its continued inclusion