Human alliance IS busted. If you bash a heavy their minigun has to rev up again. The health boost lets you be a bit more aggressive than usual, and invisibility may be useless against bots but it has more of an impact against players than you'd think. Lastly, you are severely undervaluing teleport, which is the strongest item in the kit. Teleport behind someone and you'll destroy them as any offensive class. Turn the corner and teleport down a hallway to escape the enemy and be back in the clutches of your team (easier to do with +40 hp). Or, teleport the OTHER way and disappear like a budget spy, ready to pounce. Teleport lets you also easily access verticality without having to be soldier, scout, or demoman.
The best classes for human alliance are sniper and heavy. Invisibility is a huge asset for sniping across the map, the extra health prevents dying to a quickscope, and with teleport you can access spots easier and escape instantly if attacked.
Heavy, however, seems to be the class this race was created for. Just teleport into your enemy's face or behind their back. This even works against other heavies, they'll stop revving anyway with bash. You have clearly not played as/against a teleporting heavy for you to think it's "a neat trick at best." If a heavy is sitting revving in neutral territory and sees you and teleports in your face, there is NOTHING you can do to save yourself. You WILL die, and likely even die twice if you happen to have resurrection. And if you're pushing with your team and see yourself take a crocket or headshot? Teleport around the corner and back into your team. It's instant, accurate, and has good range.
In short, wake up, Jerry. Teleport is busted and the other abilities give more utility than you give them credit for.