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.
Ok first off blaming that it's another unit to micro is a very bad excuse for saying it's a poor unit. Furthermore if you're losing it to getting flanked then you obviously haven't prepare for that situation. My advice to you would be secure you're flanks and make sure the medic half track is always a a safe distance and preferably behind a shot-blocker.
Secondly when the truck heals it heals everything at once within it's radius. Therefore the medic truck is much quicker at healing larger groups of infantry than all of the other factions medics. This works increasing very well in 2v2s, 3v3s and 4v4s for obvious reasons.
Thirdly, yes it's fragile and it should be so. If you're losing it then you've obviously got it too close to the front lines.
You're fourth point about it being expensive, slow and terrible acceleration does not out weigh the pros. Okay so it cost 250 manpower and a bit of fuel so does the soviet medics in terms of manpower. The fuel requirement is also needed as it is after all a vehicle which as I previously stated can heal and reinforce wherever you need it which I must stress is a HUGE tactical advantage.
Lastly you shouldn't be comparing it to a standard half-track which can reinforce on the move. Both these units serve different roles. If you're trying to use you're medic truck to reinforce on the front lines you're doing it wrong.