James Stern kindly responded to my musings. Since his comments are so thoughtful, I thought I'd give them their own post:
For my own part, I am inclined to think it’s is generally best to have a conflicts rule that seeks to validate wills (or their attempted revocation). But the real question here is who decides? Should the adjudicating court supply the conflicts rule it thinks best or should it apply the conflicts rules of the situs? The whole premise of conflict of laws is that the forum will sometimes supply someone else’s contrary view of the best way to resolve the case. So it’s not enough just to say, we want to uphold the will, etc. We also have to conclude that the decision is one that we should make and not someone else. As you know, I’m alluding here to the doctrine of renvoi.