100%, it's the 21Century, time to start using 21Century materialsInstead of steel armor I would suggest the use of synthetic materials such as fiberglass/Kevlar/aluminum/carbide laminates for light weight but good shrapnel/fragments protection mounted on the new 4 door jeep frames.
Low tech for the most part , proven design (jeeps been around for better than 70 years) light weight . Also look into using small pick-up trucks with fiberglass/Kevlar/aluminum/carbide laminate sheets that are cut to fit like pieces of plywood .
This will allow the most flexibility/lowest cost/lightest weight/highest protection .
You will not get light weight “bullet proof” vehicles even with modern synthetic materials(against rifles/machine guns) however you can go a hell of along way towards protecting folks from bomb blasts & shrapnel fragments without the weight of steel armor.
100%, it's the 21Century, time to start using 21Century materials