Global Skillshot Ultimates

They're all on ADCs. They're my favorite abilities, but only ADCs get them. I'm a terrible ADC. :c Why is it this way?

Really though, is this an intentional decision? I can see why they might be considered oppressive on say, a mid, who is likely to focus more on their ability scaling and also tends to be burstier (making a long-range execute useful more often) but... I'd love to see more. Weird ones. On junglers and supports, why not?