I have to admit, I've never heard of anyone even second guessing just replacing the rim, or at least riding it until maybe a crack develops and then replacing it. I don't think the wheel is going to self-destruct on itself, but I do think that a crack will develp at that spoke hole. To me, this seems to be "on par" for Sun rims though. Every Sun rim I've ever ridden has developed cracks in various places, and sometimes in multiple places simultaneously, generally in less than one good season of riding. But to be fair, it's been a number of years since I've built up a Sun Mistral product. Personally, I say get yourself a good Mavic hoop and do a rebuild before the weather gets really nice!