Arty can 1-shot the EV if you get the artillery strike directly above the EV.
Skyhammer also has 120 health, making him average and pretty easy to kill with a few headshots. The other fire support mercs, being Kira and Arty, don’t need teamwork to kill the EV and can kill it in one cooldown, Kira’s laser just sits on the EV and does damage over time, while Arty does all the damage at once in a concentrated area.
He’s balanced for a starter and he’s one of the main ammo jockeys, so yes he is a team player, which is why people get mad when you refuse to drop any ammo and get everyone killed, which loses entire games. There are objective points like Bridge where there is NO ammo near the objectives so defense needs ammo jockeys to hold out at all. He also only has access to one burst rifle and his other rifles are fairly short-ranged by comparison. Sure he can be useful with that 10 extra hp compared to the other fire supports, but that doesn’t make him better at all.
His ammo also has a cooldown, fairly short, but that doesn’t make it endless, you’re meant to stick to your team and constantly supply ammo instead of in short bursts. If nobody needs ammo, just drop a bunch on the floor for when they need it. He is nowhere near a lone wolf merc. A real lone wolf merc is such like Phantom, where his abilities don’t warrant that he stays near a team and nearly none of them are beneficial to teammates in terms of support. Vasily is also somewhat a lone wolf as he sits behind the front line and picks off targets from a range. If you want a an actual commando, go Thunder or Fletcher, both can take a beating and have high stopping power.