I admire the ingenuity of the long putter and the belly putter. Someone woke up one day and thought: "There has to be a better way to putt," and he figured out something that WORKED. One of the best amateur players in the country putts side-saddle with a mid-length putter (at least I think it's mid-length). His name is Randy Haag, and he's from Northern California. And he doesn't care how it looks, he just goes out and KICKS YOUR ASS.
I say: Good on him for figuring out this devilishly difficult game such that he can compete with the best amateur players in the country, even as he approaches 50 years old.
By the way, I know several guys who use the belly putter who do NOT anchor the putter. In fact, Kuchar does not "anchor" his belly putter at all. How could you ever write a rule that eliminates the belly putter for those not anchoring it. I just don't get the crusade, I guess....
BTW, I have used a long putter in the past, but had better success with the "Heavy Putter" to cure my yips. I'm now back to a standard length, standard weight putter, but I encourage golfers to use whatever works best for them.