Meh I think it's a stupid idea. It wouldn't stop the vets from having newer characters to domination the noobs and would also raise the question of just what you would rank people on. WP, SP? KDR? Number of matches played? Even ignoring the head ache that would cause, and more than likely something stupid like what they currently have where you can't even pick what game mode to play on for new characters you still have the problem of player base.
Dust has maybe 3-6k players on at any given time right now, less just before and after shut down. Past midnight pacific you already get into countless matches where the teams are uneven and way below 16 on 16. You cut up that 1-2k player base even further into rankings and there would be no one around to play the game. Not to mention the possiblity of the player base drying up further as people get sick of Dust for one reason or another and jump into new games.
I like Dust over all, but imo the only real thing it has going for it right now to make it competive against other games is the fact it's free. If I was paying for Dust I would be very disapointed in how little it's progressed so far. With a ton of great games comming out this fall/winter on PS3 and other wise it's not hard to imagine Dust player base getting even smaller if something amazing doesn't happen soon.
Imo the best thing to do is not a ranking system, but for CCP to give us the PVE content it talked about ages ago. It would allow people get the hang of the game in a some what safer enviroment. After all the AI can never be as dangerous as real people. --- "That is not just scraping the bottom of the barrel, that is lifting the barrel up and poking some of the slimy sludge growing underneath the barrel."