I don't think this will improve consistency much. Units like the ostwind, Brumbar, and ISU152, rely completely on their main guns to counter infantry so will still get lots of kills against clumped up units. Buffing MGs and removing cover mechanics for tank MGs also makes things like using a sandbag wall with guards behind them a lot worse against medium armor for no reason. Pintle MG upgrades are not devided evenly. Medium and heavy tanks often have the same number of MGs so either the MGs will have to be inconsistent in strength or the main guns will still need different AI strength, which will still lead to inconsistent wipes against clumped units.
I don't think you read the OP... Just skimmed....
Uneven allotment of pintles was addressed. Additionally while not explicitly stated I figured it would be assumed that AI tanks were going to remain unique. As well thought out and totally awesome as your idea of the ostwind relying entirely on its pintle would be I'm just not sure ost could handle that....
Brummbär was also (again not explicitly) slightly touched on with talking about heavies and how they need to be front loaded with wipe potential but a pintle would allow for more consistency and thus less reliance on wipey DPS.
Heavy Armour would be a caliber above mediums naturally, I didn't think it needed to be said that a 12cm IS-2 cannon wouldn't have the same reduced AI as the 75-76s of the medium armour stated in the title and discussed in the post.
The important thing is that special units remain a cut above but your run of the mill medium is reliable and still a threat.