The current Load Balancer abstraction is in beta, and provides very little functionality. It is hard to create a load balancer that is actually useful if one uses only the portable abstraction.
It would be great to take it to the next level and refactor it and add all missing features. Currently there are only two providers that implement it: Amazon ELB and Rackspace Cloud Load Balancers. Taking the features they expose as a reference to build a proper abstraction can help improving and making really useful so it can be used in the real world.