MoonSong
Rules-lawyering drama queen but not a munchkin
Classes are by their very nature rigid. There is absolute no difference in having feat and ability progress outlined on a separate Sorcerer class table than having it with the Mage class which the Sorcerer is a subclass of. It also doesn't increase the page count by a whole lot, probably less than a a single page of tables and class information for two classes. All of these classes have to be detailed as subclasses regardless. The Sorcerer may even have to have a special table for Spells Known anyway. Also, having Sorcery under the Sorcerer class is no different than having it under the Mage class. It would take just as many paragraphs.
The key major difference between having a separate Sorcerer class is that abilities that are not apart of Sorcery are tailored specifically for the Sorcerer instead of ending up with a Sorcerer with Brew Potions and Scribe Scrolls.
Not to mention it makes it accessible again, facilitating a straightforward character creation and removing most of the potential confusion while eliminating a key source of mistakes. It doesn't matter how simple and novice friendly the actual sorcerer is, if that is buried under a pile of fiddly customization choices, it will not see much play beyond more experimented players.