Heroes 5.5 WarGame Edition - Tactical Edition.

Any general increase in the number of troops leads to a gradual deterioration of the gameplay, because...

Well, let's start with the fact that I didn't suggest increasing the number of troops, precisely for the reasons you described. The suggestion to lower the level of the Knights is because having a Knight next to Angels and other semi-divine creatures seems strange - although for heroes, this absurdity in an army of humans is the norm, or maybe I'm just exaggerating the status of Tier 7 units.