[HoMM V]9 Race - Swamp! Is it needed?

I came up with the main special ability for the SWAMP faction. "Swamp Sludge" reduces the speed of all enemy units by 3 and also reduces initiative by 30%. Combined with "Swamp Mire," this gives a -4 to movement speed. A unit's speed cannot be less than 1. So now, Dragons will only be able to fly 5 squares!)))