Did someone call for The Thing? (Will open in window.)
I had two experiences with the USMC Ontos, once when Marines accompanied a convoy I was riding shotgun on. They dropped a couple of the things into the back of a M54 5-ton truck, loaded the guns up with 106mm canister, and were good to go; we had no problems that day. The other time a Marine detatchment working in a city area had a little problem with .50 MG fire in a location where a vehicle couldn't get in to take care of the problem. No worries, an Ontos crew dismounted one of their guns and hauled it and several rounds of ammo to an upstairs roof where they commanded the terrain beneath. I recall to this day a little rooster of a Marine lieutenant infuriated by the fire his platoon was taking demanding that *This! $h!t! Will! Cease!...This! $h!t! Will! Cease! IMMEDIATELY!....
And once the Ontos crew was in place and set up, it did.
The MoGas engine of the Ontos would need to be replaced with a more modern Diesel, the armour could stand to be upgraded with a Kevlar/Nomex padded interior to spevent crew damage from armour spalling or stray round penetration, and adding a TOWII/Jevelin/Ground launch Hellfire to the 6 guns would be a worthwhile addition- see my comments above about a missile tank killer, but substitute the Ontos' recoilless guns for the 25/30mm autogun I suggested; there's probably room for a mix there- and other modernization would be required; SINGCARS radios and a PLUGGER GPS unit, at a minimum. But it could be done, and cheap, and I'd rather take one of those into combat than a Stryker....
And I bet that several Ontos, so outfitted, could be carried in a C130, maybe even one or two in a C47 $hi!hook helo, which is more than a Stryker or even a Tow HUMVEE can say. Was the Ontos amphib-capable? Even if not, it's certainly no worse than a Stryker or HUMMVEE in that respect.