Not sure where feedback for the whatsapp proposal is to go. But here is mine.
Personally i'd be reluctant for things to move to whatapp for a couple of reasons. First, large whatsapp groups can quickly become overwhelming (a bit like a chaingang!) and the messages with relevant content (in this case details of the club ride) often get lost. Second it is also not good for prospective members wanting to see what is happening with the club. Even if they are not yet signed up many will still read the forum before deciding to come out on a ride, if the club rides are organised and discussed in private then it excludes those not already in the group from participating (even if just as an observer at the beginning).
Perhaps if an information group could be set up so only those who are admins can send messages then it might work out better? The messages would then include the details of the weeks ride (route, where and when to meet) but with discussion about it then being directed towards the bunch forum.