Магия "Might & Magic Heroes VI"

I think the strongest spell isn't Time Stop, but Wave of Nagas (the last Tears skill). Stunning small units for 2 turns and pushing back large ones (especially when the enemy has advanced to your positions) is very valuable. It also gives Nagas an incredible advantage in the form of a quick rush. Following Kirin, Kensei units attack enemy archers (for example, against liches), and you can forget about those archers for the rest of the battle (due to Kensei's ability, which reduces damage taken by almost half), or finish them off before the wave ends by focusing on them.
In my opinion, attack magic is only needed for mage heroes and only in the last mission of the campaign, where it allows you to quickly and without losses clear out neutral creatures at the beginning. In other cases, control spells (Petrification or Time Stop), healing, and defensive spells are much more useful.