MMH5.5 - Heroes of Might and Magic 5.5

This is why all end perks are stronger to compensate - Preparation, armor spikes, Crushing blow + chain attack combo

As I mentioned before, +1/+1 doesn't seem very strong, but +2/+2 (immediately, without waiting for level 20) is good (we are essentially spending 2 level-ups for such an effect).
So, for 2 level-ups: +2/+2 (which is less than +4) and +7.5% to retaliatory damage, which is approximately +4 (in total).