I explain in more detail my example, and you yours)
If you want a heavy that can shoot twice, cross train as a sniper.
A Sniper with a “Quick Aim”, takes any Heavy Weapon (with 3AP) and shoots Twice per turn. Is the sniper pulling the trigger faster than the Heavy?
Your turn.
You concentrate more on the next shot in the chaotic battlefield situation, allowing you to ready, aim and fire a little bit quicker than usually, but it’s mentally tiring (hence the cost of willpower, your “mental health”) and requires training (thus the requirements of being a sniper and the talent-points cost).
But this is totally off-topic…
Starting Sniper pulling the trigger faster than Heavy with HW and Assault with AR?
Sniper, at the beginning of the game - 2 shots from HW, 3 shots from AR.
add
If you want a heavy that can shoot twice, cross train as a sniper.
What? To shoot faster, (but less accurately) Heavy and Assault must learn the Sniper class?
This is definitely on the topic. And your examples are waiting for an explanation, if you have something to say.
So you know, that fully trained Heavy can pull trigger even faster, but you prefer to keep silent about that. It looks like trolling now.
If I say that all the skills are broken, then where are the examples from the competitors, from other games?
Is it OP / broken?
No, they are not OP/Broken, because other cross-class combos are just as strong, if not stronger. “OP/Broken” only exists in an environment, if everything is “OP/Broken”, then nothing is. You might say that the “time to kill” is too short with that, or that it’s “first turn/hit wins RNG combat”, but neither is “OP/Broken”, just a different gameplay-design, which you might not like.
Why are my examples waiting an explanation? Which “example” is waiting an explanation? Magic being magic in a fantasy game needs an “explanation” with believable Earth-logic? Or just “class A can use skills for less energy, thus combo-ing that with high-cost skills is a nice synergy”?
They’re not pulling the trigger faster, they ready the weapon, aim then fire “faster” when concentrating (Quick Shot), just like I said. If your translator can’t understand that, it’s not my problem.
I would first understand it as a language barrier with google-translator, but it does creep into trolling that’s for sure.
This is another “formulaic justification”.
This is the topic you would love - Think combos are OP, don't use them
Like Potkeny said… Cross training of classes wasn’t invented in PP. PoE has it, PoE2 has it, original D&D had it, AD&D has it. There are tons of games that have it. I personally happen to like the ability to cross train in PP. I’m not a big fan of how they assign the ability perks and being able to cross train in another class gives me the opportunity to get the maximum benefit from the randomness of those perks.
I actually like this idea for at least the simple reason that it’d radically change Quick Aim on 1AP weapons. No longer would we be able to Quick Aim x 5 on the same character and endlessly fire a PDW at targets. PDW would go up to 2AP I assume, and Quick aim reducing it to 1AP. Can’t just keep endlessly firing as long as you have WP anymore, and would need to at least mix in an Onslaught or something.
Another even simpler way of doing that is make direct-fire with any weapon cost a minimum of 1AP, regardless of skill reductions.
So you would no longer be able to ‘infinitely’ spam pistols & PDWs, and Rocket Launchers wouldn’t get a free shot out of Boom Blast (which enables a bombardier to spam 3 explosives per turn as it stands).
… or even more with the new Vidar Grenade Launcher, 1 AP ormal, 0 AP with Boom Blast. The only thing to do is dual class Assault to Heavy or vice versa because the Vidar is an Assault GL. And because it is an Assault GL any soldier with the Trooper perk is also proficient to use it (if this isn’t a bug), so with a bit of luck you can build something like this:
Only limit is the Inventory and resources to refill the ammo …
I would vote for this:
Yes, This is exactly what I mean, 2,5 AP in current AP value, and Beresrker’s melee weapons can be adjust to 1,2 AP
I see the core of problem with HW in lack of mobility, WarCry and Jetpack do not fix it properly in my opinion,
there are more ways, but that are kind of “big changes”, so I would like to try/test them in mod first, before implement to game, some ideas can be good in theory, but bad in practice
The mods can be a good testing tool here
Sorry Guys for the late reply, I see, that I started constructive discussion here 
I would to add that Phoenix point’s terminology uses Action Points (AP);
the time units (TU), Movement points (MP) are just different names for same mechanism, which works different in various turn-based games, so I use just AP to avoid misunderstand
In the XCOM & Gears tactics & Hard west, the 1 move (=1 action) costs 1 AP, and does not matter, if it is for 4 squares or 2 or just 1.
In Phoenix Point, a soldier can move 5 times for 0,2 AP and still have 3 AP ; technically, PP works with smaller numbers in the background, so would not call it “major overhaul” , just “adjustment” of the AP value (“granulating”) ,
for me, the 4AP in PP looks very limiting, and I guess, it does not allow to properly set the AP amount for Heavy Weapons and Melee Weapons, and some other gear
How much costs Sniper’s pistol with Quick Aim skill? 0AP? like mentioned Vidar Grenade Launcher above
Edit:
AFAIK, he can move x times for 1 AP and x is dependent on his speed stat.
I would explain it the other way around, movement is dependent on the speed stat of the character and these define the movement points (MP; 20 speed = 20 MP = 20 tiles straight ahead) and these are divided by the AP, actually by 4.
I.e. with 12 speed a 1 AP action “cost” 3 MP, with 16 speed it will “cost” 4 MP and so on and of course vice versa, with 16 speed a soldier can move up to 4 MP at a “cost” of 1 AP, using only one MP more would then “cost” the next AP
Is that understandable in any way?
2nd Edit:
That said, to reach what you suggest it would logically only need a higher divisor for the MP/AP division. Of course only logically and pure theoretical, that doesn’t automatically mean it is simple to implement 
Yes, every weapon that the Sniper is proficient with can be used for -1AP with Quick Aim.
That means, with Quick Aim the Sniper needs 0 AP base off for pistols and the Neurazer and with weapons proficiency (dual class or personal perk) PDW, mounted rocket launcher or Destiny III, Vidar, not sure about melee with vengeance torso, never tested … and maybe I forgot some other.
I forget to notice the “speed” mechanism
Yes, I knew about this hidden mechanism, did not know how exactly it is working, because there is no in-game description, but I noticed that speed stat practically affects soldier’s movement 
So, does a soldier with 16 speed stat (and no speed penalization/bonus from armor) have 4 MP for 1AP ?
Is 1 MP = 1 Square in practice?
BTW this is another Phoenix Point’s UI problem, that MP is hidden
So if we double the AP value (4AP->8AP),
than we need to halve MP value? ( I.e. 1AP = 4MP → 1AP = 2MP) it is not complicated math,
but You probably mean to technically implement
Yes, at least this is what happens when increasing (or decreasing with penalties) the speed, you can move more (or less) for 1 AP.
Only direct adjacent but not diagonal, this costs more. That said, under the hood it seems to me that the movement is calculated as exact as possible with floating point numbers and the rounded result (should be always rounded up) reduced the MP. Of course pretty much only an assumption, as you said, it is badly explained in the game.
I meant simply double the AP and let the MP as they are, so 20 MP / 4 AP ==> 20 MP / 8 AP (Edit: what exactly leads to 1 AP = 4 MP → 1 AP = 2 MP with 16 MP [speed]) and then of course increasing the AP cost of all abilities.
Theoretically easy but we know nearly nothing about how it is really implemented and so can’t say how much effort is needed to change it this way.
Only thing, what i founded in game related to movement system, was the speed stat description in soldier tab.
Anyway, it looks that it is just unnecessarily complex
Is it?
I think it is just bad explained, but how it behaves in the game is IMO pretty nice. A good compromise to a more complex TU system and with more AP it would be even nicer
LOL, 1 point in Speed = 1 tile movement. Movement per AP = Speed/4. How more simple can it be? 
Well, in detail and under the hood it is bit more complex, because 1 tile diagonal movement > 1 point of speed.
Edit:
For instance, a character can move with 5 speed points (I would still prefer movement points), AFAIK:
2nd edit:
Additionally I assume that the little jumps over small obstacles cost more MP than usual, very often observed in Synedrion heavens with all their little glass fences everywhere.
3rd edit:
I messed up the numbers for the special case, corrected now, little brain dead moment
4th edit:
“right angle” is meant in 90° angle to the other direction don’t know how to name it correctly, but a picture can maybe help:
5th edit:
changed “diagonal” into “right angle” … language issues, sorry
