No body has any opinion on the Tucker armored car?
The Tucker Armored Car was a deathtrap worse than anything foisted on the U.S. military during WW II. Nothing like a high speed, top heavy, insufficiently armored vehicle to get you a pile of white crosses. The U.S. Army tried a modern version of the Tucker when the came up with the up-armored Humvee. Didn't work any better in 2003 than it would have in 1943.
The Tucker Power Turret, on the other hand, was a very clever design that appeared on just about every U.S. bomber built of the war. Tucker, as was his history, managed to never make a dime off the design.
Brilliant guy, lousy businessman.
Regarding the basis of your OP - There is no reason to assume that using the Christie design would have made a bit of difference in U.S. tank doctrine. As has been said here and elsewhere time and again there was absolutely
nothing wrong with the M-4 Sherman design. It was, in many ways, the best design of the war, remarkably reliable, easy to fix in the field, fast as it needed to be (does little good if a tank, or combat car, can move at 50 MPH if the infantry is moving up at 20 mph in the back of a truck and if the fuel trucks are only making 15 mph), and able to be modified into an amazing variety of vehicles.
The problem, if there was one, with American armor in WW II was in the basic U.S. doctrine. American doctrine was specific, tanks supported infantry, specialized tank destroyers killed tanks. Those TD, BTW, were pretty effective as tank killers, unfortunately the doctrine was flawed to the point that it seems almost nonsensical to us today.
If anything a Christie design would have made things worse, since the actual design was seriously limited in load capacity, something that would have driven the Army to even greater preference for light tanks.