I don't know if it was posted here already or not. I found an interview with Alain Penasse, one of th organizers of Ypres Rally, in which he explains why they don't want to be in the ERC anymore.

Some important fragments:
"(...) there are too many rallies on the islands which make it very difficult for a privateer team to cope with because of the huge cost and workload of that."
(...)
“We have to get more centralised rallies, maybe one in England, one in France, one in Belgium and maybe one in Greece or one in Eastern Europe, but not like it is now."

“The championship is too much spread out. It is more complicated logistically to do European championship than to do European rounds in the World Championship, in fact. You have to go to Azores, to Grand Canarias, you have to go to Cyprus, as well as going to Greece.”

More details at http://www.rallysportmag.com.au/home...happy-with-erc