This is exactly why level 5 needs to be in EA - so players can give feedback on its implementation.
Agreed ...
I just believe that corect order is: First invent ... then test.

IF (and this is just my own theory based on what i see on 5lvl NPCs) they didnt invent it yet, or they arent satisfied with this hot needle half-solutions they use ... then there is nothing for us to test.
I mean ...
We are in EA for more than a year (and half? not sure) ... that allone probably gave them enough isight to know how people react on half-done and placeholders mechanics.
That said ... i know we just get half-done and placeholder fog of war.

But if im right here (and i realize that alone is HUGE if) probably somebody in Larian have seen it and thought "this isnt exactly what we had in mind YET, but its good enough to show as work in progress" ... someone else then probably could look at reactions and extra attack mechanics and thought something like "nobody can ever see this".

And even tho they multiple times repeated during PFH that Fog of War is still worked on, and that it is just first atempt, and that it will work better when released ...
Look how many topics and mentions that mechanic get. :-/
Can you imagine that amount of negative feedback after we would simply get another action on level 5???

If it isn't added until Full Release, then Extra Attack (and more level 5 features) will be some combination of: buggy, unintuitive, frustrating, over/underpowered, or allowing unintended actions.
Again agreed ... that would be worst (even worse) case scenario. :-/
I really hope they dont get that horrible idea to release before basic mechanics like this and reactions (wich i believe are hold back just bcs Larian is unwilling to leave their comfort zone) will be polished to perfection.
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if they have yet to figure how to do it that's really worrying.
A little ... but we still have at least year (personaly i believe more like 2 ... since i doubt it will be Q1 2023) that should be enough time ... hopefully.
And if not, they can allways push it back even more.
Question is if someone is even working on it ...
I mean if (and again we dont know, so i can only gues) their roadmap is something like:
Classes > level 5 > reactions ... (i know, its simplified as fuck but you get me)
Then there is no reason for them to even think about Extra Attack until they implement all classes, bcs nobody will ever seen it anyway.
Also (and this is a little overstepping boundaries i know), there is a possibility that some clever moder will come with elegant solution for them.

not to mention there are no reactions implemented yet.
That is not exactly true ... we have "some kind of reactions" since the day 1 ...
They just come with so many problems, it was imediatly rejected by many people ...
but i don't see much complains or mentioned anywhere on these.
I would say more like "not anymore" ... a year back almost every topic was talking about reactions, and in almost every PFH Swen ensured us that they ARE working on some way to implement reactions ...
Last time i have heard mention them specificaly was Patch 6 PFH.
If i recall corectly Swen specificly told us that they dont want to make reactions like they are in Solasta bcs they are affraid it would prolong the combat wich is allready quite long ... many people on forum expressed disagreement with such statement (after all, if you are refusing or accepting reactions ... you have at least something to do during enemy turns

) but they seems to made their minds here.
So if i had to gues, if someone is working on it, that person is probably trying to find some mid-ground solution so you dont spend all your spellslots during two rounds ... but on the other hand you dont need to confrim every AoO you may use. :-/
Personaly i believe i have allready found the solution, but since it didnt get much possitive reactions, i gues my idea was not as ideal as i thought.
