If you're getting hit by D.Va, Tracer, Moira's orb, etc., you'll only get put on cooldown for one second (or maybe even half a second). If you catch a Rocket Hammer to the face (or something with similar or greater damage), you'll be put on cooldown for two seconds. Intermediate damage receives an accordingly intermediate cooldown.

This would instantly establish an excellent balance paradigm - it helps to keep Sombra viable in a rumble situation against a Tracer or D.Va, but allows heroes with a significantly slower attack speed and higher damage per shot (Pharah, Reinhardt, Torbjorn when using primary fire) to shut her down more consistently.

This is particularly good in the case of Pharah, creating a massive increase in effectivity based on skill ceiling (i.e. whether you hit the Sombra with splash damage or a direct hit) but also allowing the Sombra to get some traction if they play well.