HuggesI've been through FOUR g400's in the past year. All the of them developed the same chord/tracking issue. I can happily say I've safely switched over and ordered myself a Zowie.
You didn't do any of the advice on taping the cord down or getting a cord bungee did you?
Cause I used a g400 for about 2 years while playing competitively and for the past 7 months have been using it almost daily at my work (I have an office job so it see nearly 40hrs a week of use now). No issues. I have been using a g400s for almost a year now for competitive. No issues.
Everything else you said is perfectly reasonable. I own a couple zowie mice myself some of which have my own nitpick issues sensor get dirty really easy, older/maybe new ones too zowie mice have horrible input latency on LMB and RMB, 1000Hz is really jittery (fixed with newer ones if I recall), and the weird DPI steps.