Why are summoners so neglected?

[Ririta]

Also summons do not have 1 attack. They have 5 each. So your comparison to BLM doesn't work well.

Only the level 20 and level 40 ones are unique, and of those, only the level 40 ones matters; so that's the only one that needs to be balanced (why the heck is Contagion still tied to Garuda instead of the summoner themselves?)