I wonder about how this might work in practice and how effective it might be. What gets me thinking might mostly be a matter of it not being fully fleshed out (you mentioned there was a bit more to it).

TLDR; I think the "pass priority till my next turn" button would save dramatically more time than the core idea of the post would.

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Actually, after writing the first half of what was likely to be a multi-page essay I started looking back and thinking that the amount of analysis I was putting into it was probably overboard and longwinded. In short I think the concept of a programmable action system would make the game worse for a majority of the player-base and that the players that it would make the game worse for are the exact type of players that usually enjoy multi-player tcgs.

I'm happy to elaborate if you wanna discuss it though , just didn't wanna come off as that asshole that thinks he knows everything.

Having macros and not having them will be same for experienced players, without macros they will do this quick, problem is that new or not experienced players need more time to act and this will or not speed them up.

The problem will be with players WHO need time to Think or read cards, You cannot force them to do this quicker unless they can do nothing. Also You need to learn them how to take shorter Turns and why

In my opiniom Smart UI will do more to speed up game. For example

If its oponent turn and You have 0 resources or dont have quick action its auto pass to respond

Or You have 1 resources on turn 1 and no Card with cost 1 pass Button is starting to count down 5 seconda, so You know You cant do anything and push IT faster or IT will do this for You if You wont do this in less then 5 sec

Also Smart buttons will be cool option, something like pass till end of turn with exeptions, exeptions can be player action becouse You have verdict, so IT wont Ask You to do anything if oponent player Play a troop, IT will trigger only on action

There is many more Smart UI thing that can be done, those are examples

Someone can tell that some of ideas i said might be helpfull for oponent, if You auto skip some situations IT might mean that You have no respond but its casual format and this issue isn't big deal, unless 2v2 format will be competetive, then we dont need Smart UI probably, experienced players will Play quickly

*Disclaimer: I make a number of claims in the post. They might not all add up, but I spent a considerable portion of my night writing this up and feel pretty confident in them. Feel free though to point out any specific claims and we can see if they hold within the context.*

Going to put forth a few scenarios:
a) At the end of your current turn you have all of the information you need in order to know exactly what you're going to do for the entirety of your next turn.
b) Somewhere between the end of your current turn and the start of your next turn you know exactly what you're going to do for the entirety of your next turn.
c) After you have drawn the first card of your turn you know exactly how the rest of your turn will play out so long as you are not planning on drawing any cards.
d) The line of play for your next turn is not clear until that turn has neared its end.

All of these situations are possible and already occuring, each of them occurs a non-zero % of the time. Your system doesn't propose that A happens very often (and Hex would barely qualify as a strategy game if it did), but rather that as the moment that requires a decision from the active player approaches, the obvious lines of play become more clear.

Programming the potential plays while other people are taking their turns boils down to busy work. You're required to set up a number of scenarios where you will only result in AT BEST using one of those options and at worst none at all. In those moments players are not playing the game, they are jumping through a series of hoops so that they can potentially speed up the game on their own turn for the benefit of everyone else they are playing with. As player count increases the likelihood that they use any of their pre-programmed actions decreases since the number of variables being introduced to the game between the time they program it and the time the execute is increasing.

Furthermore, it is never actually reducing the amount of time that the active player spends making a decision on their own turn. If they're proficient with the system they still need to have spent the same time considering their plays regardless of whether this system is in place or not. The system merely cuts down on the time that it takes to execute the specific action they've programmed. Rather than press multiple buttons on their own turn, they input one single action that then follows their pre-programmed prompt. However, and I mention this again, this system is only ever dramatically increasing the amount of input a player gives the client.

Normally
A player executes their turn with X number of actions.

Under the proposed system

A player executes their turn with Y number of pre-programmed actions. [Y will always be less than X] But each of those Y's represents MULTIPLE X's that took place during someone elses turn and only one of which went to use.

In the end for the most proficient player in the world [in terms of a player that takes zero time to make a decision and they are clairvoyant enough to never program any unnecessary actions] this system is only ever saving the amount of time that it takes to input X-1 actions into the client. For all the other players, they still need to spend the time to think about what they're gonna do and that is the most time consuming part.

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Player archetypes and levels of proficiency
***This was my 2nd of 3 points I was going to flesh out. It largely regards why the type of players that typically most enjoy multiplayer formats are some of the least likely players to use a feature like this. Let me know if you want me to elaborate on that idea... it is getting late though and I'm gonna get back to watching Westworld.***

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Lastly I come from the school of thought for board game design that if you want to make your game better then the vast majority of the time the best place to start is by removing things from your game. Added complexity does not equal added depth or entertainment value. This sentiment holds true for this type of feature and I will give some examples why:

-The system adds a considerable amount of busy work to playing the game for very little return.
-It still doesn't address some of the biggest culprits in terms of 'time suck' in multiplayer ex: someone needs to use the bathroom and they have priority so everyone has to wait, as number of players increases those issues increase more than proportionately.
-It is something that would require significant engineering and QA time despite it being something that only a fraction of the players playing multiplayer would use which themselves are a fraction of the overall player base.
-It is something that would occupy additional screen real-estate when that is something that is already at a premium.
-It is a feature that would be considerably harder to execute on anything other than a PC.

It would probably just be better and much easier to implement (while likely also saving more time in game) to just have the ability to bind your 1-9 keys to the corresponding cards in your hand... press that key then click a target.

Eh, it's still an interesting idea & something like it could definitely work for combo decks, but it almost seems like they are trying to avoid that specific type of combo deck that repeats a series of steps from existing in the first place. Those are some of my favorite decks in other games. On topic, I'm a fan of the "shotgun" approach, if 20 ideas results in one awesome 1 that is a pretty good success rate.

I'm pretty sure macros like that would benefit 0.05% of players (same amount that bothered to read the full post, no offense it's just excessivly long). So, why not make it just for yourself and save the devs trouble. Last I checked there wasn't any system preventing interractions inside of rules.
I'm using several small macros myself.
One that onRighClick reads card's name, retrieves the price and puts it into clipboard, and it works fine.
You could make the macro you described for yourself.

I think the easiest way to speed up multiplayer is to make it so teams only get one turn that they all share each round with players still having their own resources and thresholds and the chain being first come first serve.