Thought it migh thelp to have one more opinion…as someone already said differently, your client probabaly doesn’t like the bounce because they can’t actually see the photos, but I’d bet they’d like it if it just slowed down or maybe even paused briefly on the best photos. Most clients don’t (or can’t) specify what they don’t like about an effect…just that they either like it or not. I often shown clients the same exact effect with some minor tweaking and they love something they previously hated.
I also concur about always having to drop some photos in those types of projects…the only other option is to accept the fact that you’ll constantly lose (and hopefully regain) your audiences attention throuhout the piece.