Although Deadlock is a MOBA, the item system is similar to what you see in a lot of roguelikes/roguelites. A common category of item in those games are ones that decrease one stat in exchange for giving a larger boost to another stat for better item synergies. An example could be something like
Vampirism:
T2 Vitality item
Predecessor to Leech
-29% HP (nets out to -15%, due to the t2 vitality bonus)
+20% Spirit Lifesteal
+20% Bullet Lifesteal
+5% Cooldown Reduction
+10% Weapon Damage
Heavy Ammo:
T1 Gun Item
-10% fire rate
+25% weapon damage (+6% from t1 gun item not included)
+30 Health
(If my math is right that nets out to roughly the same DPS increase as Rapid Rounds)
Glass Cannon is a pre-existing item that fits this idea.
Vampirism:
T2 Vitality item
Predecessor to Leech
-29% HP (nets out to -15%, due to the t2 vitality bonus)
+20% Spirit Lifesteal
+20% Bullet Lifesteal
+5% Cooldown Reduction
+10% Weapon Damage
Heavy Ammo:
T1 Gun Item
-10% fire rate
+25% weapon damage (+6% from t1 gun item not included)
+30 Health
(If my math is right that nets out to roughly the same DPS increase as Rapid Rounds)
Glass Cannon is a pre-existing item that fits this idea.