But when you consider than finally USF tier costs you 180F while T4 270F (210 if skipped T3 which is something too hard) you would expect that T4 units will be quite poweful. They should reward you for expensive teching instead of relying on cheap call ins.
Yes it should. But you can't do that if the other side can't equally tech. And that's what it was like in the first year of the game, and it was terrible.
Because one side had a late game and the other didn't ostheer clearly had an advantage as the game went on, and to compinsate soviets had to have a dominating early. Both sides complained and here we are. The game still suffers for that bad early design. If I had my way every faction would have a T4 and every call-in would require tech.