Poor spell selection made me feel very limited in what I could do compared to playing a Wizard. Damage could be nice with Quicken + Spell but not really on par with the big damage dealers like SS Fighters, and my resources were more limited than theirs. My big once per day is a meteor swarm and a quickened cantrip, which I've hit for 160ish damage, all well and good, but other classes as you know can do this a lot more. A wizard shapechanged into a Dragon will get a lot more mileage out his 9th, or putting foresight on his SS fighter buddy will equate to lots more damage effectively.
Main issue again was poor spell selection. Playing a Wizard you can pull out the right spell that saves the encounter. Sorcerer you couldnt. What you could do was nova damage though, and twinning spells like scorching ray felt as natural as a fighters action surge. It felt right on a class that was supposed to be more damage focused.
At lower levels when our Sorc finally started twinning we were like "Ah, so that makes up for the other 99% of combat when you're tossing around cantrips for 3-4 damage". Seriously slow start to the class, and now it's even worse.
And for those reasons everyone at my table is agreement this errata is trash.
Looking forward to some of the Sorcerer options coming out of Unearthed Arcana status, and yes, Princes players guide is helpful. But we haven't fully integrated those spells into our campaigns yet.