This is a good thread that talks about elite armored doctrine and how it is gimmicky, ineffective commander. I felt the same way when I watched some streamers use it.
Scavenger for OKW is the best rare one for the faction. For the USA, mechanized and rifle are the best.
http://community.companyofheroes.com/forum/company-of-heroes-2/company-of-heroes-2-general-discussion/68019-elite-armour-doctrine-useless-for-ober-kommando-west
Because vanila armies never had a gimmicky, ineffective commanders before, right?
60% of commanders are gimmicky and ineffective.