I can see an argument for better pay* for MPs to make them independent and to attract people who are successful in other careers who would find it hard to rejoin (unlike lawyers).
* I mean competitive and enough to remove other "allowances" and the "need" for other roles, therefore they are acting for the electorate, not shadow characters.
I disagree about other roles. IMO they should be part time - they make far too many laws as full timers and in any case it would help to get "real people" in the Commons. But I can never see the job being attractive to successful people - the public would never stand for pay in the millions. And then there is the contempt issue. And finally an ordinary MP is largely powerless. So can you see a successful businessman used to controlling, and directing an organisation on a multi million pay packet being interested in being part of a talking shop?
Mind you if Trump is an example of a successful business man in power, do we really want it anyway?