I've done a bit of gliding at Booker a long time ago. I got hacked off with the uncertainty and all of the waiting around. For me to get back into gliding i think that you would need to move towards the "powered flying" model, where we'd have a slot (one hour, for example) dedicated time with an instructor - to cover how ever many launches that could.
I never really understood why that couldn't be put in place. Might increase the costs a bit with needing dedicated "glider fetcher/pushers" but these could be doing it in exchange for flying anyway.
Just my two centimes!
You're not far off the mark, There is some what a "waiting around feel" sometimes, especially when busy. The main problem is a Gliding Club is a Club.
I think for most PPLs joining a gliding club this will be very strange, unlike a flying school club where you turn up at your allocated time and fly as a customer. At a gliding club there are paid individuals, but the majority of the work is done by members.
For most Gliding clubs/societies/centres', they operate as a club from a day to day basis, but they also act as a business (courses/trial flights) that have to be dealt with professionally.
I've been to Booker a few times and during the summer season it seemed they have employed seasonal instructors that specifically deal with trial flights etc, and also around 15+ instructors that are just club members. On top of the year round CFI.
In regards to the waiting around aspect, I recall that there is a daily schedule for each instructor on duty, with allocated times for flights (trials, courses) and they have priority. If you just turn up on the day and they can fly you, they will, but you'll be bottom of the list. Sounds Fair.