Having been on trips with anywhere from 28-44 travelers, my feeling is that the expression"the more the merrier" does not apply. Group travel is an exercise in hurry up and wait, which many of us happily tolerate for a variety of reasons, not the least of which is fellowship. Nevertheless, I feel that increasing group size will significantly detract from the comfort and mobility of the group and from the overall enjoyment of the experience.
Captain Larry's example of "coaching and de-coaching", is a case in point. With the few extra seats many of us share to hold our back-packs, day-packs, jackets, canes, shopping bags, etc, being taken up by additional passengers, our "stuff" will have to go into overhead bins. De-coaching will become more like the horror that is de-planing. And, yes, I believe that it can take 15 minutes.
While moving around in the open air may be minimally impacted, think about queuing up at each and every place we stop: comfort stations, snack and souvenir checkouts, passport checks, scenic overlooks and photo ops, group dinners, the breakfast bar. Whatever we've been programmed to wait for will require waiting even longer.
Someone mentioned Whispers, which have been a wonderful addition to group touring, but wouldn't it also be nice to be able to make eye contact with the local guide, observe her gestures and expressions, and be close enough to pose a question, the Whisper being only a one-way device. How many folks, if standing 20 feet away in a crowd, will simply suppress the need for that bit of information?
Also, wouldn't it also be preferable to stand in front of the scene, or painting, or local craft the guide is expounding upon, rather than inching ahead by degrees long after she has moved onto something else? And THEN, finally, to be frustrated upon discovering you have a question about it as she moves on to another topic?
Call me a Grinch, but I think increasing group size is a BAD idea, and a probable deal-breaker for me as regards future travel with GCT.