
Baarogue |
Note to those without a Player Core, the wording has not been changed from the APG version on AoN except to replace 'spell level' with 'spell rank'
The feat doesn't say that it needs to be or counts as a spell your familiar knows, only that it must be on your tradition's spell list. I don't see any problem with it being one your familiar does know though

Xenocrat |

Not choosing one your familiar already knows gives you the opportunity to (slowly, throughout the day) prepare a new summoning spell you don't know, choosing one your familiar already knows just gives you the flexibility to prepare/swap throughout the day without the opportunity to get new access to a new summoning spell.
Pick the one you're most likely to want to use/swap to through the day, eventually teaching your familiar the spell won't be that hard if you want to.

Finoan |

Be aware that summoning spells aren't good at summoning a powerful combatant to help take down a big challenging enemy. Summoning spells are for summoning a creature that has a useful utility effect, or to have them body blocking a bit of damage from low level mooks before the summoned creature goes down to them.
I think that when you take the feat you have to pick which summon spell you gain (the feat doesn't say that you get to choose the spell each day).
No, it doesn't have to be one that you already know. I also don't think you gain any benefit from having it be one that you already know. You can already prepare a heightened version of the spell without knowing it - you only have to meet the spell's minimum rank requirement (so you couldn't prepare Summon Elemental in a 1st rank slot, but you could swap it in to a 4th rank slot).
You can certainly pick a spell that you do already know solely for the ability to prepare another copy of that spell later in the day - replacing a spell that you prepared during daily preparations.

Baarogue |
I don't read it as requiring the choice when you take the feat or even per day. Such feats say so and add that it can't be retrained or only changed by retraining. I read it as being chosen whenever you want to use 10 minutes switching a memorized spell, as many times per day you want to spend 10 minutes doing so

calnivo |

I don't read it as requiring the choice when you take the feat or even per day. Such feats say so and add that it can't be retrained or only changed by retraining. I read it as being chosen whenever you want to use 10 minutes switching a memorized spell, as many times per day you want to spend 10 minutes doing so
Generally:
You have a point referring to feats that explicitly state when a choice gets "locked-in" and needs retraining to be changed. On the other hand, concerning rule interpretation, I fell flat on my face a couple of times before, so I've become really cautious up to paranoid. (Especially when I see some forum users obviously deep in PF2e rules pose differing interpretations. (Tensely looking around.))Firstly, I really like clarity. In this course, I really want to see that potential, important limitations are presented in a way as unambiguously as possible, instead of relying on exegesis of single words and grammar.
Besides this, I generally like feats that open up a wide variety of options. That holds even more if they have several built-in restrictions already, like 10 minutes additional prep time, or the inherent slot and creature-based power limitation. A class feat that requires you to know that you will need a Summon in 10 Minutes already isn't what many "character optimizers" usually call a power house ... ;-)
Specifically concerning Rites of Convocation (existing in APG already: Deeplink):
I really want to follow the free interpretation, i.e. summon spell chosen at 10 min prep time, NOT locked-in at feat selection time. (For the reasons mentioned above.)
Frankly, after having another look and comparing class feats, especially the mechanically similar Druid's Elemental Summons (PC1, pg. 129, right column, existing in CRB already: Deeplink), I see that interpretation threatened. Have a look. Effectively, the free interpretation would result in a feat that for Arcane or Primal witches did everything of Elemental Summons - because you could choose Summon Elemental as in the Druid Feat - plus more.
Now I'm not saying that should be forbidden, unwanted or undeserved. It might even be the intention, that they wanted to allow Witches these options and designed a feat that was probably better than the Druid class's counterpart.
To knowledgeably decide if class options really are invalid or "Imba" requires more than me just randomly picking two abilities and pointing out which was better. And I'm not even saying Rites of Convocation, even in its most liberal interpretation, actually would be Imba.
I'm just noting my observation, which is based on past experience: When encountering equal level class feats, A and B, and feat A could do the same as the feat B plus more, it usually got the "too good to be true"-vibe (smell, accusation, however you want to call it) pretty quickly... Sometimes rightfully from my POV - in case I found A really overpowered; in other cases I wondered whether it was actually feat B being underpowered and really needed a buff instead to become (more) attractive.
Anyway, I'm not the authority for other people's games and let's never forget Rule 1. I'm just interested in
- how you think current rules (RAW or RAI) are,
- how you think it should be in this case,
- improving my general understanding,
- improving clarity in rules descriptions and the game.
TL;DR
Calnivo wants rules clarity; would like Baarogue's free interpretation; is afraid Finoan is right; explains why.

Baarogue |
Some classes are better at certain things than other classes. Yeah, my reading of the witch's feat makes it more flexible than the druid's version and could be called objectively better. But both of their level 4 feats are still worse than a class feature wizards have the option to take at character creation. I think that's okay because the wizard had to commit to that option instead of other class features instead of being able to add it to their skillset later. Druid's flavor doesn't suggest itself to giving them the range of choices a witch might have, so I'm okay with their version being more limited than witch's
And looking further, since I thought it odd druid was limited to elemental, druid does have a level 2 version, Call of the Wild, that allows subbing in both summon animal or summon plant or fungus. It looks like the designers wanted to limit druids to either picking a lane or spending more feats for more options
edit: I'll also note this line at the end of Rites of Convocation, but lacking from the druid feats: "The spell you replaced must be of at least the summon spell's minimum spell rank." I believe this is because the spells listed in the druid feats are already lower rank than the feat's level, while the witch's feat is meant to be flexible enough to allow picking summon spells available later in their career, without requiring they wait until that later level to pick the feat (if that sentence makes sense)