Raise Zombie mana cost

Why is raise zombie mana cost that high?!? You gain nothing from spamming the ability, you just chilling with minion never dying until you get to fight a 10 mod rare monster well balanced and he start killing every zombie but you CANT SUMMON THEM FAST ENOUGH TO BE ABLE TO DO ANYTHING!! Cause ypu are a summoner and you need wayyyy to many passive tree node to be able to invest in mana regen and why would I even need to invest in mana regen has a summoner with 400 int. Fix your game ggg why do I have shitty mana regen at 400 int jesus christ what do you expect from me. Im complaining but lets be real it is one of the best league ive ever played except for mana management. Continue the great work and sorry for my bad english

Just to clarify the mana cost is at 127 mana tn there is no world where this is justify. Loll now I stop, thant you to look into it