As a post-doc, should I pursue incremental research or revolutionary research?
Consider that he may be correct.

There may not be an upper bound, but there is certainly a lower bound to the 'boldness' of work that will move you to the next level. 

Indeed, while progress is usually incremental, few good faculty positions go to individuals that produce 'usual' work. Your senior advisor has certainly had time to feel out what is likely to succeed.