Policy wonk is the lamest term going. Paul Ryan calls himself that and he is a fucking moron.
There are literally inexhaustible supplies of Civil Servants who specialise in writing and implementing policy. It isn't actually that hard. Believing Ed Milliband is smarter than Jeremy Corbyn doesn't make a difference when it comes to headline issues like tax rates and re-nationalising trains.
I agree with you only in so far as anyone can and will call themselves a policy wonk, regardless of knowledge or talent. There are no real qualifications for policy work and no standardised performance metrics to enable reliable comparison of candidates, so mere interest in politics coupled with reading a newspaper can give a person the impression that they know a lot about policy.
But being a good policy-maker isn't really
that simple. It can be quite complex - more so than basic level of political analysis on a internet message board. Identification of problems, identification and evaluation and synthesis of evidence, development of options, argument for preferred option, development of realistic delivery plan, consultation, design of legislation, implementation, evaluation. Working with local authorities, arms length bodies, private sector organisations. Ensuring compliance with relevant legislation and policies. Being aware of flaws or gaps in evidence. Admitting failure.
Intelligence and competence
are important factors. Ability to work with numbers, work with evidence, interpret statistical data, make rational judgements on incomplete information, avoid fallacies or biases in interpretation or judgement, etc. It's not quantum physics and I don't pretend that I'm a great mind. But this doesn't come instinctively to a lot of people - just look at the course of the public debate on issues like Brexit. Reasom subordinated to emotion. Evidence subordinated to narrative. Brilliant political work. Disastrous policy work.
So if, hypothetically, Ed Miliband wanted to renationalise the railways because he's evaluated the industry and the evidence and concluded that nationalisation is the most cost-effective way to meet his policy goals, and Jeremy Corbyn wants to renationalise the railways because the fares are too high and fat cat private train companies are creaming off the profits, then in my book Ed Miliband would be the better policy-maker. Both might reach the same conclusion - and let's assume it's the right conclusion - but I would still be wary about trusting Jeremy Corbyn because he reached the right answer essentially by accident, using a dodgy method.
Of course, that is all hypothetical as I don't know the motives for each candidate's policy choices. But Corbyn gives the impression that his policies are driven largely or entirely by ideology rather than by evidence.
I have really very little enthusiasm for ideology. I am human, and I have my beliefs and prejudices, but I always aim to look past my personal feelings and understand the cold reality. Good policy is ruthlessly pragmatic - as scientific as possible in its approach to evidence and logic. Corbyn is simply not a pragmatist and therefore I cannot see how he can govern as a policy-maker.