Of course there is a solution that resolves everyone's issues at the same time. You have a tank to start with, but allow the weapon systems to be mounted on folding supports so if needed it could for example lift a weapon above the height of a building and still fire while in cover. Then just take that a stage further and build in articulated supports that can fold out to lift the entire vehicle off the ground in cases where needed, say like crossing a river when it is too deep for tracks and you do not have time to wait for a bridge, or simply crossing terrain that has undulations far to uneven for tracks to cope with (something like a boulder field).
Problem solved since what you actually have is now a mech, that also is a tank and can perform the roles of both. If we had the metallurgy technology and ability to create speed and agility of movement then I could see it as a natural evolution of a tank as they would no longer need to ask for things like bridges or airlift support for most tasks. Yet keep all the functions of a tank with it's inherit benefits.