What are those changes?
Experience has taught at least me, that having the 4.6 release branch go on for so long, and having so much development on both HEAD and oacs-4-6 continuously, has caused frustration, because some cool or useful new feature was on the wrong branch, and had to be merged forward, then backwards, etc.
So I think we should try and keep the 5.0 release branch as short-lived as possible. Which is why we haven't branched off yet, because a later branch point means less divergence, means a happier life.
Also, if we can do the 3-month release cycle, then having your work postponed from one release to the next isn't too bad, because it won't be that long before the next release goes out. Is my thinking.
So: What are your changes? And could you hold off committing for another few weeks?