Redneck: Sorry

- should have known that from the context. Yes, you are correct about the Sherman's superior speed versus most of the German, and most British, tanks (I forget the numbers too - darn it).
In answer to your question of how we can even contemplate replacing the M1A2 with the Stryker it's simple really - all you have to do is believe is that US Forces (or at least the US Army)
will always have:
1.
Information Superiority and will know what our opponents are going to do before they do it.
2.
Air Supremacy, which allows us to eliminate our opponent's air forces, suppress his ADA and devastate his heavy units
before they can make contact in serious numbers with the Stryker units.
3. Superior
Air Defense capabilities to protect our units from enemy air attacks in the event they can mount a serious air threat.
Thus, a high sided 8 wheeled thing the size of a fracking bus with no more armor than a heavy duty garbage can and less firepower than a M113A3 can pulverize any opposition. I don't doubt the training, dedication or ability of the soldiers in the Stryker Brigades, but I do not have much faith in their equipment - or maybe I'm just getting old and too traditional.
Have your looked at the loss rates between the M1A2, M2/M3 and USMC LAV units? Pretty clear that the LAV (close cousin to the Stryker no matter what anyone says) had a horrible time surviving in Iraq - speed and moderate firepower (25mm cannon versus an M2HB or MK19) were not enough!