EFC is based on parents' asset and income, plus Kid's. Generally by the time kids go to college, their contribution is almost nothing, if not nothing. I think since it is based on parents' ability, parents should pay to the EFC amount.
by setting UC as the standard, however, you limit your kids' dream. Let's see she/he work hard and target a better school, are you willing to tell her/him that: "no, your dream should end at UC because I am only willing to pay the amount." It is not simply hurting, you give your kids a reason that they don;t have to work hard since UC is relatively easy to get in.
I believe EFC is a better way to go. If kids choose to go private, the cost is higher, and the EFC is a little bit higher bacause it counts parent's primary residence equity. However, it is still fair enough since only 6% the equity is counted. if they stay in a state university, fine, the EFC is still there for them. The most important is that the cost above EFC is generally covered by a school, either by grant, work/study or loan. If it is loan, it will be lower interest loan.