I have always loved sacrifice. It fits into the lore ya know? Its interesting. And up until I read this thread I thought it was 100% efficient and that was it's only saving grace.
The pathfinding thing is the death of it, and I think range would help it. But there is still the component that its your build power and getting rid of it is pretty much always a setback not worth it. I think there are a few ways it could be improved or changed.
~ Boosting efficiency. Easy
~ Adding effects. AOE Heal, AOE auto reclaim
~ Changing effects. Remove build, have it do something else entirely that kills the unit. A last stand thingy? AOE Convert of enemy units of same tier. Regen field in build radius and health drain to death for unit. Satic shield of certain value (uncontrollable unit like ion storm, but a shield).
~ Putting on more units. Would labs be combat viable if they had a 100% sacrifice? Multiplied by veterancy
~ Unit simply detonates, every one the power of an ACU explosion. Can chain react. This is the Way.
Also, since we are talking useless economic bonuses, lets make a "recycling center" for the cybran. Like a land staging center you just hit a button and the unit goes to the nearest suicide booth and is turned back into mass at a high rate. GENIUS.