The Zanzoken (sp..) could improve with PL though by taking you further with a single use, or using less ki. Admittedly, as your ki pool increases you won't notice its usage as much either, so the idea is almost implemented already. I'd have to say though, that I'd prefer the distance not improving in favor of the amount of ki usage. It doesn't take much just to do a bunch back-to-back manually and it allows a finer control on where you end up.
I can see this becoming an incredibly useful ability with the suddenly larger-seeming maps. Perhaps transformations should be the deciding factor in how much ki a Zanzoken costs...
As to the instant transmission, Goku says he travels as a beam of light, not at 1000 times its speed. When he describes it to Trunks the english dubbing (best I can do..) of his words were approximately: "It's amazing how much ground you can cover moving at 126 thousand miles a second." that's more in the neighborhood of the speed of light but still off by about 54,000 mps. Additionally, the first Brolly movie (only loosely connected to the series, but what the hey) shows a quick glimpse of Goku while travelling via "instant transmission". He's clearly moving, not disappearing and reappearing instantly somewhere else. But that's still pretty hard to square with most of the other stuff you see him doing with it in the series.
Luckily; WHO CARES! Hahaha! I'd rather contribute ideas to the game than argue about a show that doesn't stress that much about internal consistency anyway.
Anyway, thanks for reading.