If the ISU-152 were to receive a range buff like the Jagd and elephant to be near or equal to them you'd have to remove the HE rounds. Essentially it would become an infantry wiping machine as well as a long range tank destroyer. It cannot be both or it would be a a no brainer in team games to combo it with mark target or other disables.
The band-aid switch ammo type can go and yea give it a pure anti vehicle role

It hasn't been an infantry death machine in a long time either. to the above as well, just like how the Jagd and Ferdinand are no brainers? Strict AT capabilities and Jagd range, as the one side have two massive range massive Armour and the other having glass cannon Jacksons that bounce so reliably off of panthers and above is working great.