I'm of the opposite view - publish only if you can prove it. If you reward half results, the field will be deluged with half truths. If someone publishes a hypothesis you're working on with only a half proof (and stands to gain the future credit), then there is little incentive to continue doing the work to prove it.

This was actually a major issue one of my PhD advisors had, since it led to poor foundations for the field with little incentive to ensure their validity.