My friend for what seems to be your first try its not bad, but i have to agree with what Vietlord said. Also you need to have AA weapons as part of your base tech tree. The only group that doesn't have some kind of base tree AA weapon is the PE but they have the Flaks in their bases so (supposedly) they don't need them.
Another thing i like is that you used a lot of ideas from quite a few people (me included as it seems). Mixing and matching ideas is very good but you should avoid things that are TOO similar to the existing factions such as your Bike scout.
Otherwise i got to say its looking pretty good. Keep rollin' my friend
PE Armored cars (not a real AA weapon) fire at aircrafts but everything else is true.
Youre infantry units pop cap are also wierd.
1man is usually 1pop (not counting snipers, constripts and some wehrmacht infantry) so 4 man squad should cost 4 or 8 pop.
Youre units are similar to egsisting ones and there are too many of them. Just look at PE or UK. All they need is 2 medium tanks.
88mm Bunker is OP. Try a weaker gun.
I like the idea of buildings without crew (panther turrets) so that the no recrew bug wont affect them... just saing.
12.8cm Selbstfahrlette L/61 - "This will make the Priest look like a mortar". You allready have a Wespe call-in. (600 MP is a little too much for a vechicle on a light tank chassie). You also have SS Stormtroopers and Flampanzers to fight trenches and emplacements.
If youre making a doctrine with artillery try making it weaker (the artillery part) than the whole UK arti tech tree.
No arti call-in can be better than the Priest - Balance.Hummel fires only 4 shells and has no MG becouse of balance (becouse PE can boobytrap, disable points).
Callipolie is only good at killing infantry blobs becouse US has a Pershing AT call-in.