The overall size and mass of combat vehicles needs to come down, or we will be in a situation where our forces have bacome immobilized. Tactically, jumbo sized vehicles will have difficulty fitting into urban and complex terrain, be more difficult to hide and likely get stuck more often once they leave the roads. Operationally and strategically, they will stress the logistics system due to increased demand for transport, fuel and special maintainence and recovery needs. One only has to look at late WWII German AFV's and the proposed Allied countervehicles to see the problem (the 1980 era "Block III" program of the US Army and the escalating weights of MRAPs and AFV's tell us the cycle is ongoing).
While I am not against extra protection, we need to look at finding other ways to protect vehicles and platforms. Material science can provide some help, materials like "Spectrashield", M5 fiber, ceramic composites and aerogels can be used to provide passive protection with much less weight than high density steel armour. Preferential protection of crew stations and vehicle layouts which place vehicle mass in the way of potential threats (like the Merkava using the engine block to prevent frontal penetration of the crew compartment) is next, followed by signature control (making vehicles harder to spot by technical means; i.e. thermal blankets and radar absorbant coverings). Active measures like increasing situational awareness and active defenses should also be part of the plan (although I am not very keen on most current active defense systems since they threaten dismounted troops and personell in the area).
I would like to think that effective vehicles can be made in the size/weight range of the CV-90 family (including the CV 90120 tank) which can provide the right balance of mobility, firepower and protection for our troops in the future, and lighten the load on our logistics system at the same time.