No other Exotic literally gives you more usage from your Super. No Striker exotic increases the blast radius. No Defender Exotic increases it's duration. No Sunbreaker exotic (to my knowledge) gives you more hammers. No Voidwalker exotic gives you extra blast radius. No Stormcaller exotic gives you extra time or chaining ablilities. Honestly, though? I think they might've done it in an attempt to make Circle of Life useful.