I would say that the Puma or Bradley are around 75% heavier than an LAV, and are meant to fight and maneuver alongside main battle tanks off-road (our current Battalion structure actually combines tank and mech infantry units together). And, the infantry dismount from a Bradley directly into the fight.
I would categorize the LAV as a well armored people mover, that rapidly moves bodies on high speed axis of approach to staging areas, usually in an urban area, where infantry climb out and assemble for a patrol/etc. Or as a gauntlet runner, meant to move troops safely through hostile urban areas.
I have no problem with either...both have specific rolls.
You brought up the 25 mm. I believe that within 15 years, DU ammunition will be either banned internationally, or our own government will self-ban them. I hope the Army is researching the performance of the 25mm without DU, in anticipation of this development.
I know the LAV is quick, I had one up to 90mph on the highway heh.
We used them for assault alongside the leopards.