How far has 8x8 development come in the past two decades? Consider the above pic. You're looking at the Piranha 5 on the right and the LAV 6.0 on the left (as you look at the pic). The size difference is readily apparent. Consider the LAV 6.0 the vehicle that everyone always screams about. A dramatically upgraded version of something we already have in service.
During ordinary times that would be more than enough, but we're not living in ordinary times and the state of the art is advancing rapidly.
How far have we come? The above pic is from STRATEGY PAGE and you can see the LAV-25 (an upgraded version still serves in the USMC) next to the LAV-III (Stryker in US Army service).
The Styker/LAV-III/LAV 6.0 is a toy next to the Piranha 5 and that vehicle is dwarfed by the Eitan, Terrex 3 and Super AV.
Is bigger always better?
No. Not at all. But bigger does give an indication of advancing technology. It does give growth potential and the ability to carry larger caliber weapons and to flex into other roles (family of vehicles).
I've had my doubts about wheels but I've seen the MTVR go places a HUMVEE couldn't. The USMC Land Systems Office believes that a 8x8 can do the job that the tracked AAV does today while offering better protection, easier maintenance and still be able to swim from ship to shore.
Sometimes you just have to accept the innovation that is coming. IEDs are a threat and force survival requires that our APC/IFV provide protection against that threat. For at least the time being...wheels are king.