Looking at T4 as an investment to engineers is weird way of looking of thing but rather irrelevant.
It's not weird at all, especially for EFA as both of them literally already have infantry bonuses that unlock with t4...
Point is that EFA would have access to far more cost efficient repair engineer since the unit would cost less and yet be able to repair at similar speed.
After t4 is built. You still haven't said why that's a problem. It's locked behind t4 specifically to prevent it from being too efficient
And the other engineers still have other advantages, especially in combat
I am not sure what you mean by better since:
OKW mech truck has a cost and a tech choice attached
UKF heavy sapper have a munition cost and a tech choice attached
so they are not really more cost efficient.
If I meant cost efficient, I wouldve said cost efficient. They are better in that they exist in the first place. EFA has nothing to boost repairs stock aside from sweeper upgrade (besides veterancy, which all 5 engineers get)
Not really unless they also equip a weapons
Yeah exactly. They can still equip weapons, after equipping a sweeper. Helps them Vet up much faster hence the existence of this thread