I didn't mean to say the ambulance was useless over all, actually it is a very useful unit later on but as a starting unit it is way too expensive to be of any use. It can't fight, has almost no armor or health, it's slow as hell, and healing isn't that important early on. So why the hell is a 250 MP 10 fuel unit like this even available at T0?
OST pays 150mp/60 muni for a static healing structure that can only heal 3 models at a time
OKW pays 100mp/15f for a static healing post upgrade that can only heal 3 models at a time
Sov pays 250mp for a static healing post upgrade that can only heal 3 models at a time
USF pays 250mp/10f for a
mobile healing vehicle that can AoE heal a limitless number of units
I'll trade any of the other factions healing systems for an ambulance - its much, much better.
/edit
Yes, some factions have other sources of healing, but the ones above are their primary 'constant' healing sources. The other abilities (SPio med-crates, OST Vet 1 ability) require constant resources. Also UKF is in flux right now, with their new medic squad; so I'm ignoring them for now.