I'm not sure what you mean - his post existed before and was Mandelson's previously. Or if you mean his role on the committee, well he said himself there had been a "misunderstanding of the machinery of government" and "I did expect to have a substantial influence [over banks], which is what this [committee] provides."
Which doesn't sound that speculative so much as him not being able to do what he fully expected to do.



It probably is about fair under the current system, the Lib Dems seem to be very much the junoir partner (in terms of both numbers of cabinet seats and the prestige of them).
I don't agree on the impact PR would have though, purely speculation though it currently is of course. I tend to think they would pick up more than they would lose - they suffer more than they gain from tactical voting and the protest vote element is outweighed by the lack of motivation to vote in quite a number of areas which are safe Tory or Labour seats. I live in a safe Tory seat and the Lib Dems got over 20% of the vote, despite not having even campaigned. It is similar where my parents live as well.
Of course now there is the impact of their alliance with the Tories to factor in as well, which will hurt them I think.