Why don't you use npc summons and what would you change about them

For me it changes the fight too much and makes it feel unrewarding. Since the boss isn't aggroed at you, you don't get to experience the satisfying "dance" you have once the moveset clicks. It can also sometimes be unclear who the attack is directed at, I prefer the consistent aggro. Optimizing your punishes and finding strafes is also part of the fun for me. They do add something to the fromsoft worlds besides helping in bossbattles though.

The times I'll gladly summon is in Horsefuck Valley and the Leda gank fest (the 5v1 broke me).

Besides experimenting on my first playthrough in ds2 I hardly ever used summons for said reasons, so I dont know too much about them. Idk if ER spirit ashes are any different.

For me it changes the fight too much and makes it feel unrewarding. Since the boss isn't aggroed at you, you don't get to experience the satisfying "dance" you have once the moveset clicks. It can also sometimes be unclear who the attack is directed at, I prefer the consistent aggro. Optimizing your punishes and finding strafes is also part of the fun for me. They do add something to the fromsoft worlds besides helping in bossbattles though.

The times I'll gladly summon is in Horsefuck Valley and the Leda gank fest (the 5v1 broke me).

Besides experimenting on my first playthrough in ds2 I hardly ever used summons for said reasons, so I dont know too much about them. Idk if ER spirit ashes are any different.