I am currently working on a paper that challenges some long-standing practices within my field, but am questioning how to title the paper. Basically, the old view in the research field is "we do Y instead of better method X, because X takes too long." We show that X is usually just as fast as Y, and often is actually faster. 

Given the fact that we're taking what could be a "controversial" stance, does it make sense to put the controversial idea directly in the title, or should it be saved for the abstract.

Basically, the question is if a "traditional" title, such as:

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> Using New Method X to Improve Solving Problem Y
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is preferable to directly mentioning the issue in the title:

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> Using New Method X Makes Assumption Z Obsolete.
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Or is finding a title that suggests superiority without questioning relevance a satisfactory compromise?