Heroes 5.5 WarGame Edition - Tactical Edition.

Manticoras and wolves are only available to the Orc faction.

I see the game as more of a strategy game than an RPG.

And I only see strategy; role-playing is just one of its factors. And it's completely unclear why getting troops and magic as perks isn't considered a strategic move. Moreover, such reinforcements cannot compete with the basic army and economy; it's just an addition.

If we remember Starcraft, there, units could cast other units into the army without buying them for money. Is that also an RPG element and did it eliminate the need to develop the economy and produce troops?

Regarding those spells that are added as perks – these are special spells; they are not available in the guild in principle and can only be obtained through perks (or learned from units or heroes, also through perks). With the exception of teleport (surprise attack) and ethereal shield (invincible warriors), which are also in the original game.