Hi everyone,
Thanks for all your thoughts - so glad I could inspire such a wide ranging discussion :). For the record: I have neither accepted nor rejected the endless arguments about GP vs. Euro here, but my goal was to repair, not to replace. Regarding converting it into a fixed paddle: I considered that as a last resort, but the person who commented on the obvious advantages of a 2-piece (for me, primarily stowability on deck as a spare, which a fixed paddle cannot be used for) was right on target. My primary paddle is a fixed paddle, but I need a 2-piece as a spare for expeditions. (And for the record, as much as I admire Freya, I have no desire to circumnavigate any continents.)

I think it is also worth reporting here how disappointed I am with Werner. Their response to my inquiry was that the damage was not "due to a flaw in materials or workmanship" and would not therefore offer any kind of discount for the repair. Apparently, the fact that the damage was clearly due to a flaw in design -- the protruding release button which caused the parts to separate during a storm roll -- was not of concern to them. They were going to charge $175 to repair a paddle that I paid $230 for 8 years ago. I would no longer recommend Werner as a reputable company.

The good news is that I determined that the problem with the release button was simply that it was jamming (possibly due to grit or salt, maybe combined with a bit of binding due to the crack). I was able to get that freed up and now I just have to reinforce the crack with fiberglass cloth as one of the earlier posts recommended and I think I'll be fine.