I had the same beef when I was getting into Stack Overflow. OpenID just complicates the signup process with little tangible benefit, solving a problem few users actually have. UI-wise, it feels little better than Microsoft requiring a Passport account only OpenID is even more complicated since you have many different providers to choose from. Maybe it'll be awesome in 5 years when users all understand what OpenID is…
1) Phishing? 10x Easier if everyone used Open ID. Masquerade as a provider, phish happy.
2) If someone has their password stolen...there goes every account they have. Albeit, without open id, this is sadly often the case anyway. (Not for me, but for most people.)
3) How hard is it, really, to register for a freaking website? Name, address, mailinator email. Done, no hassle.
IF Open ID is to be useful, it has to be able to log people in with extreme ease, otherwise the time-saved benefit of not entering these reg forms will be eradicated by the complexity of the system itself. And obviously...openid is NOT extremely easy. In fact, its quite the opposite. Even for a power user...unless you're signing up for many many many many accounts, its not helpful.