Shattering Gem: my only thought for it was as a precombat buff. Not sure it would be worth while apart from that. But it is a buff that bascially stacks with every other buff.
Unless this is your bloodline spell (and I'm not going to go check if any bloodlines get it), a sorcerer is only going to get a bare handful of 1st level spells in their repertoire. I think that means you need to be really choosey about what you mark blue since a sorcerer can only pick, what is it, three? Would you really take this over a summon or gust of wind?
True Strike: At lot more spells have been made attack rolls with the errata. So probably worth revisting and rating higher.
Remember I'm specifically thinking of sorcerers in this guide
I see that it has four stars now. I think that's the right move.
Vomit Swarm. Not really understanding your comment green is good.
I can see why you wouldn't; there was probably no way to know what I was talking about unless you were in my head.
Casters often end up with a single action left over. Demoralize is a decent use of that single action given the sorcerer's high charisma. The status penalty for sickened won't stack with the status penalty for frightened. Demoralize is also a pretty commonly used action by other classes because frightening an enemy is often better than a third attack except in certain builds dedicated to high attack bonus and lowered MAP. Basically, I'd rather use Rime Slick or Animated Assault which have the same star rating and use my third action for demoralize or true strike an acid arrow.
Agonzing Despair. It just seems too low for damage for a single target will save. Yeah it has some unique features.
I think it deserves three stars. I think it at least deserves a note that if you took fireball this level and didn't take sudden bolt at level 2 you might want a spell that doesn't do the damage type that is most resisted in the game.
Dimension Door what if a small spider from a swarm gets in your pocket. You are now carrying it however unwittingly. Does it count for stopping Dimension Door? Its a question.
It's not a creature at that point. The swarm is a creature but the individual components of it aren't. I mean they're "creatures" in the sense of the English language but not in the sense of the rules, I think.
All in One, One is Al. Dominated enemines are dead enemies anyway I not going to adjust my rating for that. It's useful.
Implosion: yeah I understand the limits. Still like it. Its a lot of damage for one sustain action.
But it's not just the sustain it's also one of four level 9 spells you can cast and three you can choose to know. I looked randomly for a high level creature that you might reasonably expect to fight multiples of at level 17+ and looked in "Z" and there's the Zaaramun, a Creature 16. It has 291 hit points so hitting each one with this will take off a bit over a quarter of their hit points but only one at a time. And the value decreases if one of them gets killed before you get around to imploding him. Why wouldn't you cast weird and do 56 average damage, frighten them and possibly send them fleeing or outright kill them?
Time Beacon: the rational for my timing interpretation is that both the duration and the effect occur at the end of the turn. Page 469 of the CRB allows you to determine the order of steps at the end of your turn. So I can choose to let the duration expire which means the spell does nothing, or I can go back within my turn and not allow the spell to complete its expiration step.
I'm going to double down on my interpretation and say near infinite turns are possible. All you have to do is keep making the counteract check or not do things that would cause a counteract to be rolled.
I don't think it's intended but I did some more reading and I think you're right.
In the "Turns" section of the rules it says, as you correctly note, that you can do the list of things that happen at the end of your turn in any order you choose. So you can choose "Resolve anything else" before you choose "End any effects."
Once you can cast 8th level spells you could Time Beacon, quickened casting, Disintegrate and then basically tell your GM that you're going to rewind until your target gets a critical failure either by rolling it or by you rolling a critical success and they roll a normal failure. They can either wait for it to happen or admit that it will happen eventually and save some time and let you roll damage. That's 132 untyped damage on average. That's less than you would get by casting Eclipse Burst and Disintegrate and getting failed saves but it's guaranteed, 100% untyped, and may also trigger special effects that occur on a crit (Dread Marshal Aura for example).