Here's my opinion:
I (and I'm sure the majority of Ilkley) don't want crowds of runners turning up on Ilkley Moor every Saturday morning, it's ok for the odd fell race a few times a year but Parkrun is every weekend. People go to the Moor for a quiet run or walk with the dog etc. not to be greeted by a 5k which belongs in a city centre park. Also I fear that attracting more and more people to Ilkley Moor will only add to erosion and lead to more flagstones. Ilkley Moor is not a park and should not be treated as such. We've already got Bradford and Leeds Parkruns which are great events and in-keeping with the surroundings, I don't see why we need one in Ilkley. I've not been to Skipton or Harrogate Parkruns so can't comment on these.
I also fear that the inevitable complaints from locals about the Parkrun could reflect badly on fell runners and the fell races which have been held on Ilkley Moor for many years.