Wisconsin doesn't have party affiliation, so none. A part of me likes that and a part of me prefers New York style registration. I am wholly opposed to anything in between.
What is New York's like? And I prefer partisan regstration of one kind for two very important reasons:
1) If you want to influence a party and make it "less bad" than you constantly bltch about, JOIN IT and help change it; become a part of the voter pool and conversation. Help redefine what it means to be a Democrat/Republican!
2) MAPSSSSS
In New York, in order to vote in a partisan primary you must have been a registered member of that party at the time of the previous even-yeared November election.
For your points, #1 I'm ambivalent about since, while I'd like to make the Democrats better rather than just complaining about them, it would make no sense at all for me to be a Democrat. As for #2, partisan voter registration data is beyond useless as a predictor of anything.