That's more of a Counter Strike clone. The "abilities" are more akin to CS utilities like smokes and flashes than they are to Overwatch characters. The rest of the game is pretty much a direct copy of CS.
It's actually a technical problem - Valve is running 1 bit computers that, due to binary origins, can only represent 2 states. They'd love to release hl3, but that would require coming up with the whole new architecture - at least doubling up to 2 bit cpu. Imagine the headache of adapting all the toolchain to build the game!