Well, I do have my own feedbacks, that I will split between the horrible, the bad, the good, and the best 
- The horrible
1. All buildings needing all resources to build
I understand the "realistic" part of it (to an extent), but I do believe it goes against good design.
The 06/11/2019 note said " Second we will make the game more appealing by making changes to the progression and game pace (...)"
This changes makes the exact opposite : it makes the game less clear, it creates a noobie trap and in general more complex for no added advantage.
It also forces the player to do some serious calculation to optimize productions, whereas before you would make easier strategic decision (I am currently gated by oil, where can I increase my oil production, where can i find more oil externally, how can I shift production to need less oil). Here, it is complicated.
Note that the cost in manpower is cool with me (see below the "excellent"), I am more frustrated at Metal + Oil + Supplies + Rare Material + Food for every single units.
2. Unit speed decreasing when below 50% IN COMBINATION with units not dying one-by-one.
It is realistic, certainly, but it does not work because you cannot "detach" low HP units, so if you have 1 nice unit and one slow unit, if you merge them and the average is below 50%, you are stuck with one larger slow units and can't detach the fast unit any more. It is like the blob.
This becomes REAL bad because units now don't die when below 50%. So as time passes you get those stack of say8 units at 20%, which you don't want to merge with healthy units because it will just become at stack of 9 at 24%, that is tapping fully in your resource in maintenance - and now you are actively trying to get the large stack to die. Very unrealistic.
I feel like it should be either units die like in 1.0 CoW, or units don't die like in 1.0 CoW but they don't lose stats below 50% Both => Don't work.
- The bad
1. Units price and time of production changing depending on the level of the unit.
I realize that this is made worse by the lack of information, but currently unit price, maintenance and time of production change by level. The unit progression is power is significantly more than the progression in price, but since in a city you cannot "degrade" the levels of the unit you produce (you have to produce the best available) I am in a situation where I would like to produce MORE, weaker units even weaker but I can't.
This is especially jarring for foot infantry, where the "HP producer by hour" (eg how much HP of units you create in one hour) is better for infantry level 1 than for infantry level 2.
2. Resource almost only produced in cities + units produced in cities
It simplifies the game yes, but this means that only cities became relevant in the game. The rest is just distance to cross.
In addition, it means taking cities = Less production capacity AND way less ressource for your opponent.
I would really do the opposite : cities produce units, but not that much resources (or even not at all), and provinces produce the raw materials. This way, you have a real choice on what to defend, and one to attack
Also, note that taking the supply crates or the wheat city of your opponent early game is quite simply crippling, there is no way to come back from that in a war.
3. Units (esp. infantry) having different HP by level
It makes the game much less accessible because you need to know - or check - the HP of each unit in a stack.
I feel the progression is particularly bad for infantry (35=>60, x5 difference between low level and high level), but I would accept a (smaller than currently) progression for armor.
4. Shorter combat and production time
I know where it comes from, with more players playing on mobile, and it is a change to my advantage (I am VERY active) but I believe it gives too strong advantage to the active player. I also feel it will directly impact your monetisation, as before while could compensate less activity with more gold... but not now.
- The good
1. The new "light armor" category + the general direction of the balancing
The light armor category really gives a space for the heavy armor, and - along with the decrease of efficiency of planes - it will create more diversity in the line-up of units we see. Some further balancing is obviously going to be necessary (light tank totally crippled for instance, motorized infantry being a solution to everything, ...) but still good.
2. removal of province food & supplies upkeep.
I wasn't so sure about this change, but I feel like I am now not afraid to take worthless province, and it was a newbie trap - so good.
3. Each type of units needed a specialized building + units have a level they keep when created
While it complexifies the game, I feel like it also makes the game more strategic, forces more arbitration (should I build more units of an existing team or upgrade my factory to produce better units).
- The excellent
1. Removal of building maintenance.
No more need to activate or desactivate barracks and shipyard every time production is over ? GREAT !
2. Gating by manpower
Previously, manpower was only a problem early game, after that you were gated by other resources (usually food and oil) - something you could easily increase in production or exchange (relatively easily)
I feel like the gating by manpower - the only resources where it is difficult to increase production - would in a leaner way hamper players from snowballing too much and would force more alliance.
When balanced better, I think it will be ++.
Also, I suspect it is going to be good for your monetization
- "Jury still out"
1. The new research tree with only food & manpower.
Some proposals (as a former producer / designer on mobile MMORPG, one of which is in the "really successful" category)
On building production
Buildings would require (in addition to money / manpower) :
Barracks : Supply crates
Artillery factory : Supply crates, Steel
Tank factory : Supply crates, Steel and oil
Airports : Supply crates, oil and rare materials
Upgrading a building stops production in said building (it would emulate what you wanted to make with units taking more time to produce at higher level without the frustration for the player, and also emulate IRL WW2 Germany wanting to shift production to better tanks and better planes, but just not able to afford the output loss in number)
Unit costs (in addition to money / manpower) would mirror what it costs to make the building, so planes would require rare materials (which would represent aluminium or wolfram) and oil, tank would require oil and steel. Or course, Motorized infantry would need oil.
Wondering whether I would not make infantry units "auto-upgrade" so the players would have the choice between building infantry (heavy on MP, but remain relevant) or armor (less heavy on MP, but needs to be upgraded and can be obsolescent).
Capacity to build the "not-optimal" unit (at the lower price, this is what every single MMORPG is doing). Actually, being able to do that could allow to have better units more expensive in time, too.
Raw materials are produced in not-cities, unit production can only be done in cities.
Research would cost manpower, money, but also steel/rare materials/oil for units that require them
