Have you actually played games as OST?
Yes, several hundred games between my main account and test account. I win more often with them in 1v1's than any other faction. Is there an actual point to your question?
They are my second least favorite faction (behind Brits) but that has more to do with 4-man gren squads, that get wiped way too easily to late game indirect, than anything to do with repairs. I'd pay the same as the UKF for a late game upgrade to 5-man squads. Other than that, the only unit I think isn't worth it is the Panther, which should be buffed to be similar to the OKW version.