UNIT - Creature Balance + Visual Changes

Generally, starting with the Elven faction is quite inconvenient. These factions, like the Necropolis (as you described), or even a Necromancer, can easily break even and even increase their army size through raising undead. I think it might be possible to increase the level of the Summoning magic skill to summon a swarm of sprites, but only from zero to basic (I initially raised it to expert – I got carried away, then I tried to raise it to advanced – it was still difficult). Also, it should be taken into account that half of the units don't care about the swarm of sprites (undead, elementals, and constructs).