Doctrines are theoretically meant to offer alternatives that complement faction design.
The KV-1 is one of the most durable tanks in game, heavies excluded. The Soviets are meant to use cheap tanks to cover tank destroyers, but some doctrines offer different options.
Ostheer is meant to use high quality infantry with 4 entities but can also use Osttruppen, a cons sidegrade.
Giving the Easy 8 "Jumbo" stats would be fine imho as long as it's correctly priced
Doctrines offer alternatives but no real breaking of the rules so to speak. Ostroppen are indeed 6 man squads for ost, but their combat potential is very low. They offer a manpower effecient ALTERNATIVE but doesn't alter the way the faction is played in the end. You will still be leaning on team weapons and conserving your armour.
The kv-1 isn't out of line of soviet design either, as they were designed to have durable doctrinal options since the inception. There are no counter measures to balance HAVING to have squishy armour, it's just whst their stock kit has. T34s being the way they are leave room for doctrinal alternative of superior quality as was intended. By design.
USF was designed SPECIFICALLY to accommodate for inlu having squishy armour. Its a core of their design offset by mobility and the ability to self heal.
If you want to see what changes with no regard for faction design looks like take a gander at the brits. A fucking mess is what you end up with.
You can't simply have work around for factional weaknesses without addressing how faction strengths play in.
This is why I will never support conscripts getting a machinegun upgrade. They are meant to outlast, not outfight
Just like the USF armour is supposed to out maneuver not outlasta kv-1 that can heal itself is a horrible horrible idea... Slap the best TD in the game behind it and you might as well delete all the other commanders...