Odd how did you get them to generate more? When I clicked on my shards they all say max units summoned after the first one pops out. Maybe there is a mechanic involved that I'm not understanding.

I agree the death one can get pretty powerful but the rest of them are pretty weak. Even then the death one has to be babied until it can level up and going in for the finishing blow usually ends up getting it killed. Nevermind going into a combat with ranged units. It will be the first thing dead.

No, they are definitely not summoning more. I have a few of every shard in my game and it summons only one. The description on the shard says MAX 1 ALLOWED summon monster. If yours are summoning more then it must be a bug in your game because the description specifically says max allowed 1. If you have more it is because you built another shard.

If the summons get too weak in the end game, I think that they should increase in power with the number of shards, maybe gain 1 level / shard after the first, or maybe something like +1 Attack and +1 Defense / Shard.

I made sure not to fight any battles with ranged units when I was powering up my death shard creatures.  lol.  now they are very powerful.  plus I level as fast as possible and "rush" to get black magic mastery.  I then up my initiative on my sov. so I get some massive weakening spells fired off on the enemy.  things like mass curse render all armor useless so those late game powerhouses fall quickly before my units.

Tech progression is kinda off kilter with the rest of FE pace wise so it would be very hard to time any sort non tech requirement like magic level.

Basically however the defense and to a lesser degree attack on the bound elemental needs to be more competitive late game. I'm thinking that as they level they need to have much higher increases in non-hp stats, especially defense. You could also have magic techs that boost their summoned level. Another idea is to have different bound elementals have different tech requirements so that some only spawn late game.

Yea so sounds like there is a bug with the number of summons you can get or some mechanic we don't know about that alters the amount.

And some late game monsters would definitely help. Having no army as a disadvantage Cersea shouldn't have such a glass cannon feature.

As it stands, in my current game I have about a dozen shard summons that clog up my units UI (as they slowly make their way across the map) that I mainly use as dispensable meat shields.  I

Instead of multiple shards providing multiple weak summons, they should make the summons stronger: providing them new abilities and stat bonuses.  It would be way cooler to have that fourth death shard make my demon unit into an unstoppable juggernaut than to have that fourth death shard provide me with a weak unit that will not survive any battle in the mid-game.

You are wasting them, and that is not the games fault.