Cold down is fine as you can't have these amazing pros without at-least a few cons. Those being it's slow speed, cool down and units being unable to reinforce if it's on the move. If it had no cons then it would be way too good and effect the balance.
Cons:
Additional Heal Micro in a Micro Intense faction. Not a problem to Hans. Problem to the rest of us. Not that its hard just another thing to do...
Slow cool down on heal. Unlike every other 100% always on healing methods.
Most fragile unit I have seen in this game next to the Ostheer Sniper.
Expensive.
Slow.
Worst Acceleration.
All those things combined make it REDIC to keep alive even on a single flank against your forces.
Doesnt Reinforce while its moving. Leading pathing to make it derp around and babysit it until it stops so you can reinforce. Again another thing to pay attention too.
Cant reinforce in enemy territory. And there is no USF Halftrack. Opportunity cost here. Design says USF has forward reinforce therefore doesnt need a real half track. Making healing and reinforcing a method of turtling around the Major. Or just not at all if you dont soft retreat to it. If you do however you risk losing it.
Compared to the Forward healing truck the ONLY small advantage it has is its mobile. Would be a bigger advantage if it couldnt HEAL in the front lines but COULD reinforce like a Halftrack.
Pros:
It heals.
Medic can help healing by putting an RE inside.
It reinforces like a half track in friendly territory.
It comes early if you want.
No tech.
Lots more cons on that list then Pros from where I sit.