Just to add fuel to the fire…
In my brain, a canter = a waltz. 3/4 time. There is no fourth beat. If you were conducting it, the suspension is that moment between the upbeat and the downbeat (I always drew it as a triangle in marching band). The thirds should be even. However, I can see how a horse might throw in a “dribble” beat if they’re not particularly strong in the back end, something hurts, or out of alignment, etc.
IMO, if you can hum the main melody of The Blue Danube Waltz in time to the footfalls, it’s a nice canter – if you can’t…well. It’s hard to do that watching a shuffling WP horse without any suspension, but occasionally you can visualize it.
I’ve never heard of the canter being described as a four beat gait with the suspension being counted as a beat – even Pony Club calls it a “three-time pace with three beats to the stride.”
@Willesdon: Yes, I also find them lame looking, but I guess in WP, there’s varying degrees of looking lame.