I did Aikido for a while. Not the Yoshinkan style, mind, but I expect they're similar enough. Here's my take...
A lot of traditional martial arts get a bad rap because of the lack of sparring, even of the controlled variety, in their training. While sparring is a useful tool for anyone who wants to know how to fight I think it is wrong to discount the values of purely static training.
Remember that Aikido is a method of self-defense. It was never meant for the octagon. Furthermore, plenty of dynamic fights evolve out of purely static scenarios. While I would never recommend the Aikido method of "redirecting the flow" of a punch, its techniques for use against grabs etc. are quite effective. I've used them before... they work.
That said, the primary reason the Japanese riot police are using it is one of tradition. And giving them no proper dynamic training at all is insane. Aikido, like most things, has its place, but using it exclusively is a recipe for disaster.