That he himself (then) saw Borodino as one of his greatest achievements compared to how his generalship is genuinely viewed of that battle you/me or any other historian thinks now.
Regards his generalship a big strategic mistake was leaving lots of garrisons all over the place, that were isolated and so those men were wasted.
He was drawing troops from Soult's Army in late 13/14 but I forget the exact figures. Though again he should have united both Soults forces (united from various armies anyway) and Suchets into one army. Wellingtons force would not have been able to fight both at once