I was rereading a book about the Imperial Guard Cavalry and one thing struck me...
We often talk of the Imperial Guard's ability but only in terms of veterans and experience. I think we forget maybe one of the most important things within the Guard, what we call in modern terms command and control.
For example an Imperial Guard Cavalry Company, i.e. half a squadron had for a full strengh of 96 troopers, 5 officiers, 17 NCO's and 3 trumpeters which is a lot of commanders... plus several other at each subsequent level.
On the other hand you would usually have a General de Division commanding each regiment plus 2 Majors, one of which usually being a General de Brigade. That meant a much thighter control over each unit, that in addition was totally composed of battle hardened veterans that knew their place in the line...