Maybe easy 8 was transvered to tech so you cannot go liehtenaunt into captain with all light vehicles and still get winning hand once you hit CP and can start spamming easy 8 like no tommorow and get the lead.
USSR dependable on call ins? RLY ? you can go OPenals, you can go maxims, cons, get best AI light tank and cheapes but yet great medium tank and good suchkas or su 85. You can go every doctrine you want right now, even windustry or defensive are great doctrines now.
maybe you didnt mention m10 crush, cost = spamability and survivability.
maybe you didnt mention buldozer DMG when you stand still and attack ground
maybe you didnt mention stug e cost (70 fuel and 200 mp) on top with great AI if you get 2 (better than proswind)
maybe you didnt mention flakpanzer shock value, you can get 2 before USA can get 1st sherman
maybe you didnt mention IS2 tiger and pershing value, they can win you gave even if you was behind
maybe you didnt mention croco wipe potential, ah poor paks
maybe you didnt mention valentine maphack
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and the list goes on
You are mixing 2 different things, efficiency and availability. If you tie up M10 to USF T3, you'll have somewhat to adjust its price and the unit will remain the same infantry crusher and spamable.
You can tie up the stug-e to Ostheer T3, same will happen because the problem isn't the fact it is a call-in but its efficiency. Is anyone complaining about the USF M8? Because that's also a call-in, but it comes late in CP for what it is and completely underwhelming for its cost.
My opinion is that call-in effect isn't the problem here, it is the unit efficiency.
Call-in are also there to bring more diversity in the gameplay, if I pick Armor doctrine, it is mostly to go T1+t2 and get some light tanks and then having M10 to counter mediums. If the M10 isn't a call-in anymore or tied to T3, this strat isn't available anymore thus removing one piece of gameplay diversity.
As players, we will all end up using doctrine without call-in. Because who wants to have a Tiger if he need to build T4 before? Who wants to have a pershing if he need to build T3 before, who wants to have a ISU/IS2 if he need to build T4 before.
At this stage of the reasoning, let's all factions be like OKW, Tiger/Pershing/IS2 are all unlocked when all tiers are built because why not?
And let's go further in the thinking, why should offmap arty, offmap airstrikes not tied to tiering? Why should we only considering call-ins as super asset? isn't stukabomb able to OS 90% of any field unit? Why this strong ability isn't only available after building Ostheer T4? Why my Perhsing/IS2 need tiering but airstrike potentially wiping half of my force not? Same goes for the B-4, Lefh and etc..
Call-ins have their place in the game, now if a call-in unit is too strong (and many of them are, M10, stug-e, flakpanzer,KV8 to quote 1 of each faction) let's put it to its right place, cost and CP wise.