I would say that if Virgin are putting up £XXXXXX in sponsorship, they SHOULD have a say in how/where it's run?
You can't expect someone like Richard Branson to stump up a huge wad of cash and then not stick his oar in.
The spectators are part of what make the race so 'special' - according to most people who run it, runnerman. Having spectated several times, I can say that it's a pain getting to, from, and around the route. Anything that would make that easier would be welcome, otherwise I may give up going to watch.
As for asking the runners, NR - you ask 100 runners, you'd get 100 different opinions. The London Marathon organisers have never taken much notice of what the runners think!