I know about the compartments, but I'm specifically talking about the autoloader being a point of issue. Traditionally, they've been slow and prone to malfunction and sometimes at the cost of ammo storage and ammo type availability for all the mechanical systems necessary to make them work. IIRC The French AMX Leclerc for example also has to lower the gun to it's neutral level boresight position for each round to be loaded, taking valuable time.
Having one less crewman also means one less person to take over an incapacitated crewman or help out with in-the-field tank repairs and maintenance.
I think my solution to the problem would be something like the AMX, except in a smaller scale, or a revolver-cylinder type system that is more manageable to travel in elevation with the gun itself. Each round, it's type, and magazine position would be logged into the tank so you could have for example 4 general APHE, 4 Sabot Rounds, and 2 HE or whatever combo is best.
It's because of these issues, I wouldn't mind phasing out large tank guns for large autocannons that can better accommodate separate magazines of ammo types, and do 90% of the jobs MBTs do. For head-on tank combat, they can still carry AT missiles.