This is just an idea but I think it would be cool if the goliath came with a pioneer/radio squad (2 man) dedicated to controlling it. So the goliath would only be able to move or detonate if it's within their control aura.
Once the goliath detonates they auto retreat.
Just though this would add a bit more counter play than a unit that simply rofls wherever it likes on the map.
OR
Make sturmpioneers build radio masts (like pathfinders for USF) that emit an control aura for the goliath, meaning you have to plan ahead.....
Just ideas mind you, so don't take offense