[Daisuke]

The entire point of summon storm and multiple contracts is to zerg rush. That's the entire concept of a Grand Summoner. That's why they have tons of FP regen, astral aegis, lucky 7 is a thing, and those 3 dragons get a bonus with each other. It's also why raising the cost of maintenance was considered. Why become a grand summoner when summon storm will just screw you in any 1 vs 1 fight. This isn't "Oh well it's only a minor hindrance if you have some faith", this is "You HAVE to min max for faith AND get lucky to make this reliably worth using".
And then you have to deal with the AI itself
And then you have to deal with RNG picking and choosing the Youkai that move.
One turn your Byakko gets closer to the jammer, the next turn it does nothing and the jammer moves towards you while your Carbuncle moves closer. Next turn Carbuncle does nothing and Byakko spends his turn moving back in range. Now bring in a lot more Youkai and you can see how frustrating that would be.

There's nothing wrong with a zerg tactic when everything about GS supports it. You shouldn't be outright punished for playing the class the way it's telling you to play it. If youkai are too strong, make their abilities do less. If the youkai are okay but in combination with other classes they're too strong, there needs to be a way to separate the swarm tactic summoners with the ones that use youkai and spells (and I came up with a suggestion for that before. Increase maintenance cost and give GS an ability similar to channel destruction that costs 6m and gives FP based on the youkai you have out. This way you get to choose between actively maintaining your youkai or losing most of your FP. That also creates more ways to counter a GS focused on summoning)