Seriously the only people that want this global login system are pub-craving newbies, and loial. Like SkateR said, who cares if somebody impersonates you. If they are sucking people will know it's not you and if they are dominating then does it really matter? It's not like they're making you look bad if they are playing well.
For people like me, and 90% of the clanning community does not play public servers, and if they do they usually use an alias. So really, this global login system is pretty useless for 90% of the DP community (the ones that matter -- irc clanners). Only other people are the ones that play pub only, then the 10% of clanning pubbers.
I do not care about stats as I use a different alias everytime I play pub anyways. I do not care about being impersonated, not like anybody would want to impersonate an idiot like me anyways. Focus on improvements to DP that will help the gameplay, and not this Global Login System that seems to be giving you troubles anyways (if I have read some posts correctly)
I think the majority would agree with me here.