The summoner needs a complete change for the functioning of the filler phase, in the meantime they could add stacks to the basic spells of elemental summons.

but to repair the summoner and make it less rigid it would be necessary to completely rework the filler and if possible make elemental summon ''ogcd' spells' with instant damage,
on the other hand, it would require to split certain spells and adding others, but given the few spells the summoner has, this would make it a little less boring.

Making it a little harder would be a good choice anyway as it looks like a ''Demi-job'' with gameplay design errors actually.