Well, except for spells that say, "At Higher Levels". It's still easy enough to force a die roll.
The problem I have here is that #2 and #3 work against each other.
#2 is a narrative explanation. That's fine. I prefer narrative explanations! However, the reasoning here doesn't work with the mechanics of a spotter.
Imagine this. You're playing a game where a machine drops a meter stick. Your job is to catch the meter stick as quickly as possible. The shorter the distance the meter stick has fallen, the higher your score. You may have played this game in grade school as a reflex test. Now imagine we change the game. The second game is just like the first, except you're wearing a blindfold. Additionally, a partner next to you can tell you when to catch the ruler. Which game do you think you'd do better at? You're now reacting to your partner's reaction instead of the ruler dropping, and your partner is reacting to the ruler dropping. It's not possible to be faster at the second game.
So, if #2 is correct that it would take too much time to see a spell, identify it, and cast counterspell by yourself, then by that reasoning #3 also doesn't work because it must take more time to react to another person and cast counterspell when that person had to react to the spell, identify it, and shout out what it was.
#3 also doesn't work, but that's primarily because a familiar isn't going to be able to identify a spell. A Cat is about as intelligent a familiar as you can get, and they have Int 3. Making a DC 15 Arcana (Intelligence) check when your roll is d20 - 4 (Int) + 0 (non-proficient) is pretty unlikely.
On point #1, you are certainly correct about the "At higher levels" phrasing of spells... But, like I said, I simply don't have any cheating non-sense at my table... cheaters are going to cheat, no matter what the rules are... don't play games with cheaters.
On point #2, I simply don't buy into this analogy. My conception of telepathic communication is clearly different, in that it is instant communication, speed of thought, as if your mind is simply communicating with itself, not a secondary individual that needs verbally recite their thoughts to a blind man... so, no blindfolds, and no additional mental processing time, your familiars reaction & your reaction are essentially simultaneous... and since the spell identification game is an all or nothing game, where you catch the stick doesn't matter, just that you catch it...
I do agree that there would be a measurable difference in reaction time to a secondary source versus a primary source, but it would require a more granular tactical simulation than D&D. We're talking about a
very abstract 6-second combat round in which all of the movements and actions of an individual are fully resolved before the next individual in sequence fully resolves all of their movements and actions, etc... Given that context, both scenarios of the analogy you presented would occur in less than 6-seconds, so by D&D standards both would be equally effective.
So, I think we'll just have to agree to disagree on this one.
On point #3, I never claimed that it was easy for all familiars to identify a spells, just that it
is possible... I'll take a 10% chance to identify a spell over a 0% chance any day. Also, since we are discussing a scenario in which "variant/optional" rules are being used... If the DM is utilizing the "optional" spell identification rule presented in XGTE, it would be reasonable for the DM utilize all of the "variant" familiars as well... The Pseudodragon and the Imp both have average intelligence, bringing your chances up to 25% to identify a DC 15 Intelligence check.
I appreciate your encouragement for me to re-evaluate my assessment of the rules... and I stand by my original assertions.
We've got good rules, and we should use them...
