I think that the idea of an upgraded an uparmored Stryker to replace the now-canceled FCS is a very bad idea.

The problem is that Strykers, which now tip the scales at less than 25 tons when extra armor is added on, but it looks like an upgraded Stryker would weigh somewhere between 30 and 35 tons, and when considering that the original vehicle, the LAV, weighed about 15 tons, I think that it would be just too heavy.

Simply replacing the manned turret on the Bradley IFV with an unmanned one, and using the space that is opened up for more troops gets you there, and there is probably some space left over for the communications gear that was developed along with the FCS.