TL;DR in the end.

I really liked the mod, I enjoy the grind for EXP, leveling up, and builds. But this mod is incredibly overpowered. It goes beyond the game’s scaling and makes all bosses trivial, even on the hardest difficulty or with difficulty mods.

Up until the Spider Queen, the game felt fine and balanced. But once I got Skeleton Horde and Warrior at max level, I started melting down every boss. I tried increasing the difficulty and even added a difficulty mod, but I was still hitting like a truck, deleting bosses instantly.

For comparison: my strongest weapon right now has 41 Summon Damage, while the weakest Skeleton has 132 (Warrior has 198). My normal DPS on the Dummy Target is about 1.3k, but when I summon all 4 Skeletons, it jumps to 7k! And that’s without Dark Power! On top of that, I have 44 points in Intelligence, giving me +44% Summoner Damage.

The mod’s progression scales in parallel with the game progression, but the Skeletons feel like they’re 3~4 bosses ahead of my gear. And since I like to stop and explore the map (which I do most of the time), the gap only increase. When I face the next boss, it dies in less than a second. (Not all bosses, but I killed the Pirate Captain so fast the first time, that he just stood there with 0 HP before disappearing, lol.)

To avoid spoiling my run, I’ve removed all the extra stats, passives, and skills that the mod gave me.

TL;DR

My suggestion is (though I don’t know if it’s possible) to make Skeleton damage scale with the strongest Summoner weapon in the player’s inventory. Something like:

Skeleton Horde damage = Weapon Damage + Level%

Skeleton Warrior damage = Weapon Damage + (Level × 1.5)%

(Just an example, I don’t know if this is balanced or ideal.)

Also, I’d suggest halving the INT bonus. My best trinket gives +20% Summoner Damage, while INT alone gives +44%, which feels excessive.

This way, skills and passives won’t get ahead of the game’s natural progression since damage would be tied to the player’s weapon. Leveling up would still increase power, but no longer as an independent, runaway system.

I’m not sure how viable this idea is, or if it’s even possible to implement (But since obsidian can be exploded with normal bomb after you upgrade your pickaxe, maybe there's a way to check it), I really like the mod, I just feel it risks spoiling the main progression of the game.