http://www.britishorienteering.org.uk/news/news.php
It's clear that the proposal is trying to differentiate types of competition. With that in mind, there's quite an interesting statement from the board in their response:
The Board does not rule out a 4-level structure in the medium term if it is the best approach, but believes that the review of the competition structure (due to report December 2010) with its wide consultation should be concluded first to inform any decision to change.
This is perhaps the most sensible thing I've read so far on this "debate" as we'll actually have some decent information/evidence to base any decisions on...