To return to generalities then, few MPs resign "as a matter of principle" and when they do it is notable and to be applauded. The most recent example I can think of is Zac Goldsmith.
I quite agree that for an MP to quit mid-term simply because a better offer came along is a considerable waste of taxpayers' dosh. Perhaps there should be a clause in their contracts (or whatever it is they are subject to) that should they "apply for stewardship of the Chiltern Hundreds or the Manor of Northstead" the cost of the resulting by-election will be born by them personally.
It is clear that Mr Hunt saw the opportunity to become an MP as simply as temporary step in his career path. I suppose we should be grateful that he has at least resigned and not carried on as an MP whilst managing the V&A.
As an aside I noticed yesterday that the museum is planning to open a late-night bar with an outside terrace for up to 300 customers. The museum's neighbours, understandably are none too happy. Perhaps that's what has drawn Mr Hunt to his new job.
http://www.standard.co.uk/news/london/victoria-and-albert-museum-plans-latenight-bar-but-neighbours-say-it-will-be-torture-a3437556.html