It seems to me that the purpose of crossword setting is to provide entertainment. In that respect it perhaps resembles music, and just as there is room for many musical genres there is room also for many different types of crossword - cryptic/non-cryptic, themed/non-themed, barred/blocked, tough/easy etc, and each type has its devotees.
The skill of the setter of a puzzle in a particular series is surely to meet the expectations of their specific audience. Those attending a Status Quo concert are likely to be happier getting blasted by 12-bar blues than receiving a confection of hip-hop; likewise Listener solvers expect a tough, themed, barred puzzle with extremely accurate clueing while Daily Mail solvers expect a low-to-medium difficulty, non-themed blocked puzzle with very conventional clueing.
Guardian solvers have I believe come to expect clueing which Listener aficionados might term unsound but that they themselves would be more likely to describe as innovative and entertaining. Whilst I don't enjoy setting or solving that sort of clue myself, I'm not big on hip-hop either but I know that many people enjoy it greatly.
For crosswords to remain popular (or to grow in popularity) then their appeal needs to be as broad as possible, and if clues that are not to my taste help the well-being of the crossword as an art form then I'm happy, as long as there are puzzles which provide the sort of clues that I do appreciate. One further thought - the number of published clues is growing at a far greater rate than the number of words in the dictionary, so if innovation is stifled then pretty soon we'll just be seeing the same clues over and over again.