I just did your campaign again. Ad this time I went ONLY for the tomes and O.P items. I managed to get the stats: 59 + 14 strength, 36 + 8 Agi, 45 + 8 int. 61 - 71 damage fast (without horse) and 1925 HP (without items and without horse).
But after I picked up Frostmourne, his stats went down to: 50, 31, 39.
That is a loss of 9, 5, 6! (str,agi,int).