Armor Company for USF isn't also meta. If you have enough fuel you will most likely tech. Armor company is there to save you a day if you were on a back foot. If you werent you gonna see Shermans followed by Pershing or Calliope.
If you have advantage as a OST you won't see Puma or Stug E. You will see Pz4 + Lighting War for Tiger and JU.
And on and on...
Call ins are not meta in sense that people only play with them.
People play with them if the screwed something in the early game and try to say in game, only when on a backfoot.
If not, 9/10 will tech instead of waiting for call ins.
You say that people only use call-ins when they are on the backfoot, well in the vast majority of games, somebody will be behind in the mid-game. Look at OKW; how often do you honestly see somebody losing and go for any doctrine besides Scavenge to get an Ostwind, or Special-Whatever to get the Command Panther?
How about for Ostheer? If they are losing to light vehicle rush 4/5 times they will go for mobile defense.
And again with USF; lose your first stuart, buy another stuart, and get an m10.
The call-in meta is incredibly predictable because of how easy and safe it is. When people only use it when they are losing, then you are still going to see it in every game because somebody will be losing. The only faction that this isn't a problem for is Brits because they have no call-in mediums or lights.
Also, saying that nobody uses M4C Shermans is also completely wrong. Penals/cons into LendLease DSHK and follow up with no tech double shermans is a completely meta strat.
Mr. Smith's analysis of the current balance issues is spot on. Obviously the US mortar needs to be fixed, but will that really change up the gameplay of the game? Not really. The light-vehicle and call-in meta is what has been plaguing the game for months. In a game about multiple options and strategies, there is a big problem when literally every faction rushes for a light vehicle, and losing that vehicle or losing to that vehicle means it's gg unless you go for call-ins to make up for your lost fuel.