I was fighting the goblin army the other day and I noticed that there not very difficult to defeat during hard mode. I also fought them in a pre-hard mode world, and i easily swamped them with a full set of meteorite armor and a space gun. I'v been thinking since then, and I think I have some half-way decent ideas on how to make the invasions more challenging.
Goblin Grenadier: like the clown, this goblin throws explosives as means of attacking. However, the demolistionist attacks with grenades, walks on his feat, and doesn't spawn very often so hes not as frustrating. He appears as a goblin wearing a black soft cap and a tan shirt and pants. He has about 80 health, 4 defense, and touching him does about 10 damage. After hard mode is activated, he will spawn more frequently during invasions and have 180 health, 18 defense, do 30 melee damage, and will use bombs instead of grenades.
Goblin War lord: this unit serves as the final enemy in a goblin invasion. He will appear right before the invasion ends and killing him will end the event. He appears as a slightly taller goblin wearing a green-colored, somewhat rusted version of silver armor (no helmet). His health stands at a somewhat intimidating 650 health, 18 defense, and his attacks do 30 damage on contact. After hardmode, his health stands at 2000 health, his defense is 40, and his attacks do 60 damage with a chance to leave the broken armor debuff.
Goblin Beserker: this unit will only appear after hardcore mode it activated. Some what like the warrior but more dangerous. They have 650 health, 25 defense, and 40 damage. However, there name makes sense when after losing half of their health (325) their damage will increase to 60, there defense increase to 45, and they will start moving 20% faster then a player using an anklet of wind. There is also a chance that a hit can inflict the bleeding debuff. They will appear as larger goblins (like warriors) wearing a darker colored version of a copper chestplate and pants.
Hard mode improvements: All of the enemies that appear in the in-game goblin invasions will all have enhanced stats and some new abilities once hard mode is activated.
Goblin peon: 200 health, 20 defense, and 30 damage.
Goblin Theif: 220 health, 20 defense, 35 damage, 10% faster moving speed, and every hit will cause 10 copper coins to drop from your inventory.
Goblin Warrior: 400 health, 50 defense, 40 damage, and a chance to inflict the broken armor and weakness debuff with every hit.
Goblin Sorcerer: 180 health, 18 defense, 35 (ranged) and 25 (melee) damage, and a chance to inflict the cursed and cursed flames with a hit from a chaos ball. 3 chaos balls will be fired at once and fly considerably faster.
Goblin archers: 200 health, 20 defense, 40 (ranged) and 25 (melee damage), and the arrows shot are now jester or unholy arrows (arrows depend on time of day). The arrows will pass through multiple targets and 2 are fired at once. Also, the archers shoot faster and now have a much wider range.
All of the goblins will have a 30% chance of dropping tattered cloth aswell as some new loot.
Goblin Theif loot: random items of some value (eg ingots, furniture, weapons, etc) aswell as a goblin shiv, a unique dagger-type weapon.
Goblin Warrior loot: a goblin sheild, an accesory that gives you 2+ defense aswell as a 10% damage bonus when fighting goblins and land enemies (eg zombies, mummies etc).
Goblin Sorcerer: the spell tome Chaos ball, which works like a water book except for the fact that it does less damage but can go through walls and fire more projectiles at once.
'Goblin Grenadier: will drop between 5 and 15 bombs/grenades (depends on if hard mode is activated). It will also rarily drop the hat it wears, known as the D'emolition cap.
Goblin War lord: will always drop a peice of goblin armor (it can be a helmet, chestplate, or greaves) and more rarily a unique greatsword called the goblin's fury. The goblin armor has the same defense as silver armor but gives a 10% movement speed increase aswell as a 5% increase in melee damage. The fury is a greatsword that has the appearence of a claymore sword that has a base damage of 16, swings slowly, and has a decent range. Whats unique about the sword is that it if it kills an enemy, 5 health will instantly be gained.
If anyone had any suggestions that would make the goblin invasion better or likes my ideas, post a comment below