Threshold is rather easy like that, so it's not as if it will take any effort from anyone with decent software. You only have 5.4% failure chances for those Hacking programs if you're at 6+6. Add three dice and you're below 2%. Fading also is rather easy with those values, so to be honest, the test and fading are largely irrelevant like this. In other words, the essence of your system translates to 'Submersion programs max at a time, nearly no risk involved'.
Myself I'd make the Echo more like Quickening, let you pay 1 karma for each Program you want around and then put a reasonable limit, such as Submersion, on how many you can have active at a time.