In a certain other recent thread it seems like I've been seeing hordes of armchair theoreticians who have been making assorted claims about the sorcerer despite obviously having comparatively little play experience. Now - I like the class, and I'm not personally certain that the errata is all that damaging or at least the errata is in keeping with my personal previous reading of the Twinned spell metamagic ability; but the fact of the matter is that the sorcerer does indeed have issues with versatility. And complaints about it are absolutely on target.
Rather presumptive and carries an aggressive tone. It's entirely possible your experience might be lacking and you don't realize it. ;-)
Just to maybe clarify a few things:
* The sorcerer has fewer spells known than any other primary caster (other than the warlock...who IMO doesn't really count because of their weird casting mechanic...their at-will invocation abilities...and because the warlock can deal middling martial-level damage with a cantrip).
The sorcerer has less than warlocks too. Warlock spells known are only for spells up the 5th level and the arcanum plus invocations being them up to bard levels of spells known.
It's not that bad, however. The extra 2 cantrips sorcerers have over bards and warlocks makes a difference at low levels and simply use skills like a fighter would. Bards and warlocks know very few spells at those levels as well because the gain takes place over time, and by the time that happens a sorcerer has had opportunities to intersperse some versatility amid different spell levels. Sorcerers also have spells from which to select not available to any other arcane spell caster except high level bards with secrets. Secrets don't cover metamagic or font of magic.
* The sorcerer knows fewer spells than any other primary caster class that prepares spells can even prepare at one time.
Definitely. It's a feature of those classes. The sorcerer's draw is metamagic. Combining the large selection of preparation with peak moment power of metamagic becomes extremely powerful. That's WAI.
* Unlike casters that prepare spells, the sorcerer is stuck with the same basic known spells day after day until they gain a new level...and so cannot even adapt that very limited list to a particular challenge or situation.
Also WAI and true, but with additional comments.
Sorcerers adapt in different ways. The need to rely more on a mundane approach to some issues like a fighter might so a sorcerer on a mount might be use for speed and mobility or the sorcerer might rely on high CHA and proficiency instead of charm person.
The extra cantrip over a wizard, or 2 over a bard or warlock, gives an additional utility option or a different combat option when cantrips are the main source of combat spells for those spellcasters. Sorcerers also have a few options for specifically versatile spells like enhance ability in alter self from low levels; it only takes a few combat spells for combat so there is room for more.
Font of magic and metamagic create some versatility by making the same spells more useful by combining a few options with another few options, and alternatively, the choice to simply have more available spell slots than any other spellcaster creates options where others are out of options. A wizard who already cast his 3rd level slots or a sorcerer who already used his pact magic slots doesn't have the same opportunities as a sorcerer who can create another slot as a bonus action.
The resources require more management than prepared spells but still work.
* The sorcerer is the ONLY primary caster who does not have the Ritual Caster ability. (Although again this requires an invocation and a pact choice for the warlock).
This is intentional. Developers replied to questioning on it that it's a distinction between training and raw talent. Ritual casting isn't all it's cracked up to be because it requires preparing or acquiring the rituals anyway, and most ritual spells are of limited effect. They always break concentration. They are slow to acquire.
In the sorcerer's case, the limited spell selection would preclude many rituals anyway so it's more flavor when a sorcerer who does need another detect magic spell might simply cast it again or create a slot if needed to cast it again. Anyone who really worries about it just takes a feat so it's not a huge deal; nice to have in some cases but not a real issue.
* The sorcerer's metamagic abilities compete with the same resource (i.e. sorcery points) as spell slots. So in combination with the lack of Ritual Casting...the class often effectively has fewer spell slots. (But can nova a little better).
I don't find rituals come up often enough for that impact. Font of magic really does give more spell slots than arcane renewal and still have points for a metamagic or two. Total number of spells per day by trading in a higher level spell for lower level slots turns 1 spell into 2 on top of that when many low level spells are relevant and good at higher levels.
Usually I find every other caster is out of spell slots first unless the sorcerer is making an active choice to use a lot of metamagic. In such a case he still uses cantrips and skills. Every spellcaster runs into using cantrips and the sorcerer does have more of those.
On top of the above limitations, the sorcerer's closest homologue - the wizard - holds a greatly expanded spell list. These limitations become distinctly obvious as class levels rise. THEORETICALLY, the sorcerer's metamagic abilities make up for this. But their metamagic picks are quite limited....so when one of them turns out to be ineffective or circumstantial...it hurts significantly.
Don't make circumstantial or ineffective choices. Metamagic only requires 1 selection to match the spell selection. Choosing single target spells for twinning, quicken for bonus action extra damage, heighten for saves, or empower for higher damage on multiple dice roll spells just makes common sense.
Metamagic is more peak moment potential and it does that job extremely well. The real question would be why a person who wants to cast rituals and know a lot of spells would choose a sorcerer over a land druid, lore bard, tome warlock, or any wizard tradition in the first place because they all provide different flavors of those traits.
I find sorcerers less forgiving for mistakes in the build design process but not an inferior choice. The standard spells known of (6)/3/2/2/2/2/1/1/1/1 just isn't far off from a warlock's (4)/3/2/2/2/2/1/1/1/1 plus 4 of 5th level or lower or a bard's (4)/5/2/2/2/1/1/1/1/1 with 2 more below 5th, 7th, and 9th each. Dividing those few spells among that many spell levels over the course of 18 character levels is low impact compared to metamagic and font of magic. They all have those opportunity costs selecting spells.
I agree other major spell casters have advantages in spell selection and versatility. I disagree that this should be cause for concern because metamagic and font of magic are excellent abilities taken in the trade-offs.
The only thing that I don't like is the subclass flavors. The mechanics are fine.