Possibly a border like in Survival Games could resolve issues like this, but at the end of the day, I don't think I would support it, for the same reason I wouldn't support adding the same system as they have on the Hive. It all comes down to being unique and servers putting their own version on a game. Cube decided to have Skywars function as it does and in most cases, I think it should stay this way.
I have to also mention, that I do understand where you are coming from. People running away is not the most fun thing ever and chasing them can take quite some time, which could be spent in another game. But at the end of the day, that is still the nature of the game and projectiles will forever be your best friends. And if all else fails and the game has been going on for like 15 minutes, there is still a possibility of submitting a report and letting the person know this way, that what he's doing is no fun...