Hmmm I think your calculations are off.
Take for example, Slayers Wraps :
Cost : 3300
Effects : +30 DMG. 10% chance to do double damage
Base Dmg = 160
Base DPS with +30 = 190 / .69 = 275.36 (rounded)
Critical Damage = Extra 190 every 6.9 secs = 190 / 6.9 = 27.54
Full DPS = Base + Crit = 302.9
DPS per 100 Gold = 302.9 / 33 = 9.17
Gauntlets of Brutality :
Cost : 400
Effects : +25 DMG
Base DPS = 160 + 25 = 185
DPS per 100 = 185 / 4 = 46.25
Natures Reckoning
Cost 1500
Effects : 15% chance of 250
Critical DPS = Extra 250 every 4.6 secs = 54.35
Overall DPS = 214.35
DPS per 100 = 214 / 15 = 14.29
Incremental is also fine to use, however, difficult to adjust for crits and you have adjusted the wrong way.
It should be DPS / Attack per second. So +25 equals an extra 36 DMG per second not 17.25. The efficiency of the guantlets at level 1 is unquestionable 