I would personally prefer a vastly different setup.
Firstly I beliee you still need someone to represent the common people. They don't have to be the ones making the executive decisions, necessarily, and they don't even have to be voted in. Instead I would propose a "randomocracy" consisting of people selected at random from the citizenry, somewhat like jury service. This isn't a unique idea, and apparently the term does appear in a book called 'Envisioning Real Utopias' by Erik Olin Wright. (
http://philebersole.wordpress.com/2011/ ... overnment/]) There should be some mimimum qualifications- age, being of sound mind, possibly baseline intelligence or other method to weed out the truly unsuitable. Perhaps have a list of legitimate reasons for opting out, but otherwise it's compulsory. These people would have to stand for so many years (longer than your average parliament, but no more than 10 years), and foesake any other interests which might jeopardise their judgement.
I think you should also have some sort of council of distinguished persons as UE suggests, but as other suggest, needs to come from a broad range of fields- scientists, philospohers, religious/spiritiual persons, persons of various other backgrounds who can provide unique insight. Maybe you could have these as your executive.
It's all about checks and balances, and if you don't have some sort of voice of the people, you're probably going to get mistrust and the potential for power-grabbing. Randomocracy at least weeds out the possibility that people are seeking power, also.