I don't think that a patch will necessarily change the effectiveness of a unit in general. For example, the patch isn't likely to change the fact that zweihanders are excellent infantry, or that Pavise crossbowmen are the best choice for ranged battles as the germans. In a nutshell, I don't think that a patch will completely alter the utility of the units in general.

Similarly, like Katank pointed out, the stats don't always reflect the usefullness of a unit. A review of the unit and it's effectiveness, on the other hand, is most useful for a player that hasn't mastered said faction with said units.