I never had played for score nor care for anyone else that does. For me it takes away from the fun of the game and can lead to people being obsessed with scores to do some rather shady things to acheive it.
However, from a gameplay point of view, I don't think the system message should be upped from 2 to 5. The 2 kill requirement for a system message is a 'carrot' for new players to try and reach for. For a new player to see his name in lights can be a very motivating factor and something to reach for. If it is increased to a larger number, you can possibly lessen the motivation for new players as they now see 5 kills as an impossible number to acheive or maybe push them in the direction to do shady things to get their name in lights.
I've always looked upon the 2 kill requirement as a stick and carrot sort of thing for new players.
ack-ack