That's a terrible example. Sunbreaker and Stormcaller can already map people. It's pretty common to get killed by one and then spawn only to be killed by the same person still in their super.
Decreasing the time by 3 seconds is a dick move and makes the exotic completely useless. I could understand the decrease if the super wasn't already only 12 seconds in duration.
Edit: And Achlyophage Symbiote has been in the game since day one and has remained unchanged until now. There was zero reason to make the change that they did.