I feel like a better change for the obsidian is increase the range to 30, keep the aoe 0 and increase their speed
The reason behind this is:
1. Their niche is to kill t2 units, by increasing their range it will allow them to outrange ever t2 unit except for mml and ranged bots. By increasing their speed it will allow them to chase down ranged bots as they kite, making them a dedicated t2 killer.
2. By adding the aoe, it'll make a obsidian a t1 killer which is what zep is going for but, auroras already rape against t1 units especially when shields are added so i feel like aeon just need a t2 counter, the aoe is just excessive.