So it's a "bad" unique, as Freedom of Movemement is a "bad" unique. A hole in rules. Why? Because there ARE other spells that lets you cast while you are casting: Glyph of Warding and Contingency for example. Those spells directly state that you cast spells while you are casting. While these two do not address component handling there's to say that casting another spell IS part of the spellcasting proper and it can be assumed to work in some way. Counterspell does neither.
Put this into a ruleset that seems to be firm into the mindset of interruptions of actions being a very specific and specifically handled exception on a case by case basis and this strucks twice as wierd. Why do i assume the lack of interruptions to be deliberate? Because, contrary to what other editions and systems do, there's not a trace on how to handle Action (and spellcasting in particular) interruption. Not even "deal with it as a DM".
If "So?" is about me having a specific feeling... then i don't know what to reply. Never meant to make a case for "It must not be that way since it gives weirdness feeling to me", just me sharing.
If "So?" is about "Well there are other examples out there" then i'm unimpressed. I'm looking at 5e only and the weirdness is given by Counterspell being in 5e. Can't really say that any other edition or game is on my plate when i compare 5e to 5e.
Not really. Or at least no weirder than any other other quirky bits of the rules. Maybe I'm just used to similar things from previous editions or other games. It just doesn't strike me as all that weird. It's not like it's the first time a piece of a sub-system has had a further unique ruling associated with it. I mean, yes, reaction spells are unique compared to the rest of the possible actions and Counterspell could be considered even more unique in that instead of coming before or after the trigger it interrupts the triggering action itself.
I have no problems with Counterspell interrupting a spell. It's more about Counterspell from the person that has started the chain interrupting the very thing that started the chain itself with no repercussion that's weird. And it's weird because all that's there on RAI is a single tweet, no context, and no rule anywhere with every other piece of text apparently assuming no interruption ever except a very specific case.
But D&D has always had unique sub-systems for certain things. In 3e initiating a Grapple pulled both characters into a strange world that ignored all the normal rules of combat. In 3e readied actions could come before, during, or after the triggering event (that's one way you could interrupt spellcasting).
And the system handled that - no matter how well it did. At least, it recognised the possibility.
In 5e, Grappling and Shoving are still weird - they replace an individual attack, but only when you are taking the attack action (not an attack made as a bonus action or opportunity attack, unless a feat or ability specifically grants the ability to do them as a bonus action). Yet they are not an attack, they are an opposed skill check.
Not really. Grappling and Shoving are special melee attacks that require an Attack action to perform. If the character has Extra Attacks there are some extra rules attached. I see no problems or weirdness here, considering the system as a whole. The fact that as an attack they do not roll an attack roll does mean nothing. Those are attacks because are defined as attacks. They use skill contests and not attack rolls.
I have more problems with shoving grappled creatures prone without breaking the grapple than anything else.