I think the reason that Nintendo created the Blue Shell is because there is, otherwise, no way to target the leader once he/she has attained a noteable lead-- red shells tend to peter out over a intermediate distances. The forward-pointed weapons in Wipeout behave the same way-- they really don't reach that far, so you can only impact a lead racer that is beating the competition by a second or two.

NOT that I am suggesting that a "Blue Shell" would be appropriate for Wipeout-- I just have a new understanding for the race design in Mario Kart having played online matches in a game that doesn't help the back players. It's really a different experience