You will soon have your Windows Live ID work as an OpenID. Though many have supported OpenID, it is commendable that the Windows Live team has announced the commitment and has invited feedback. As a provider, this is one of the best things you can do, involve the user in making the system more usable.
Of course there are still pressing issues on making OpenID effective. Two of the most apparent ones are usability and its lack of popularity amongst services. The OpenID popularity is growing like a lop-sided campaign. A lot of providers, but not as many services which accept it, which will be more crucial for making OpenID more effective.
I have started believing that services are hesitant in implementing OpenID because it does not offer a full solution in itself, it is only an identity framework. That is why I think developments like OAuth and prototypes like DiSo will lead us build a complete solution.