Before I do head to head play I like to run through a game human.v.human as solitaire. I did 107 turns of v102 (Sealowe no Barbarossa) and 20 turns of v104. By human.v.human is the major powers are under human control I leave the minor neutrals under AI control. When a neutral activates, it goes to human control. I did leave Finland under AI control in the v104 run only to see 150% effectiveness infantry corps appear in front of the Soviet 50% effective armor corps. I think the Finns could take Leningrad with this disparity.
Most of my impressions relate to scenario design. There were pre-102 scenarios created that looked very interesting but were not updated. I think most of my scenario comments have been covered by others already so I'll generally hold those. My one comment on this is somewhat contradictory:
1. France appears to be nerfed in 1940 --> scenario design.
2. It takes too long to conquer France. --> scenario design and game system.
My major comment is infantry is too slow when supply is less than perfect. There is no reason any leg infantry unit should ever have a movement factor of less than two UNDER ANY CIRCUMSTANCES - even if the troops are starving. There are too many weather/terrain effects that reduce it to 1 anyway. In general, I think it should stay at three. That means that in less than perfect supply, leg and mech infantry have the same move factors. I do not understand why mech infantry is ever slower than armor at this scale (scenario design issue). It looks like the low supply action point penalty is the same for all unit types. I might be tempted to do away with the low supply action point penalty and increase the effectiveness penalty. Mobile units would get a low supply movement bonus but at least infantry can participate in the campaign.
So the reason France survives so long is it takes forever for the German infantry to move up and finish the deed.
Once v104 is fixed a little, I'll try Barbarossa. I suspect it is in no way historical with the infantry unable to walk to Moscow in 1941.
Now if the designers could create different low supply penalties based on unit type, that would allow us to really fine tune this. I would not give this a high priority.
The air and naval systems are very elegant abstractions that seem to generally accomplish their intent without adding brutal complexity.
It looks like this would be a design change that is ALMOST there. A bomber should complete its mission at reduced effectiveness even if it take interception losses. Right now, if both the interceptor and bomber take losses, then the bomber gets through. If just the bomber takes losses, it does not. In a perfect world, it would be three levels of effectiveness: no interception (no fighters in range), interception-no losses, and interception-losses. In the latter case, the bomber could take losses from the interceptor and the unit attacked. Probably not a big impact on land warfare, but the bomber effectiveness against naval units may need to be reduced. Another element of the air war that became evident in the BoB is that the weaker side (British) has to pull its fighters out of range of the stronger side's fighters. In historical terms, this would have been considered a win for the Germans. One easy way to allow the German fighters to continue to attrit the British fighters is to allow them to fly three recon missions per turn instead of limiting it to one. This will work the other way in the battle for Germany. I am not too worried about the lack of fighter escort because i assume it is built into the bomber units as they do deal some significant losses to the fighters. I'll wait until the Battle of Germany to better think this through.
I also like the naval abstraction. Naval warfare is hard to integrate into land warfare and this does a nice job. One observation is that Italian shore bombardment is completely useless to the Germans. On the other hand, the ability of German STP and AMP to be used in the Med is also a head scratcher. I would make shore bombardment more like air bombardment. Ports appear to be generally invulnerable to any form of bombardment. One reduction is all you get in a week and it repairs itself the next week. With 2500 German/Italian aircraft and the entire Italian fleet sitting off Valetta, there is MAYBE a chance those supplies do not get through. In my games, the British player generally knows where to search for u-boats each turn as they are displayed even if they just moved and have not inflicted any STP losses from their new location. Early on, there were thread comments about looking at loss reports to see where the uboats are - not with 102 or 104. Since there are only a few relevant sea zones for inflicting STP losses, the British/French can sit there with their carriers and generally massacre the u-boats in 39-40. My experience is that the German spends more repairing damaged u-boats than he inflicts as losses on the British. Plus the u-boat fleet gets smaller every turn or three. As others have mentioned, the German surface raiders are nearly invulnerable but I have gotten air hits - no surface hits yet. I would make them auxiliary cruisers so they only get three hits (scenario design). I like the naval system because it has an impact on the game without taking it over. There may be scenario design approaches to making it worthwhile for the Germans to pursue a u-boat campaign (probability of detection?), but in the current scenarios I do not see it.
The nature of coalition warfare is probably integral to the game system. It is not a deal breaker for me. What I noticed right away is that this really complicates the defense of France as a British unit cannot relieve a French unit. In addition, a French unit is as good as a German unit for blocking the retreat of the BEF. This would be less of an issue if everything were not so slow (as indicated above - scenario design) Perhaps the swap unit function can be used to address the relief in place problem. Also an issue in Africa which the scenario gets around by giving the DAK a level 3 armor corps. Who needs those Italians anyway?
There was some discussion of what happens when a neutral surrenders - the allied power units disappear from the map. I would address this in scenario design by sticking a victory point city in the location that is likely to be captured last. Works for Belgium whose army is a non-factor at that point - not sure about Romania and Italy.
As I mentioned in the wish list thread, my major desire for the game system is stacking and corps combination and breakdown. The elements are almost in place for corps combination and breakdown with the merge and split functions. Two divisions merge into a reduced strength corps and a corps splits off a division. Better would be to combine three divisions and break a corps into three divisions, but that is a bigger mod. This is all easier with stacking but can be managed with the current stacking approach. At a minimum. I would like to see an air unit stack with a ground unit.
I love this game. I'll have more comments after I try the later war, but I need a working 104 before I invest any more effort.