Oh, if you're fully happy with the feature set, there is no need for a roadmap. Or if you're buying xenforo just to kick IB's ass. But if you're desperately waiting for some features, then you need one. Again, I love how xenforo works and I for myself would switch immediately my current vB installation.
But that's for me and not for my 10k+ of users. Some of the features of vB 3.x are killers for my board, without them a majority of my users will be disappointed and leave or at least won't come that often. Let's take for example custom user titles: There's a game on where mods and admins can define the titles for the users. Really funny and it's been playing since 2003. To drop that feature is not an option.
Now what should I do? Best is to wait if xenforo comes with such an option or not. And for me it's not about the money - I'm lucky to say that my forums are financed by a sponsor - , it's about time! Time to evaluate solutions. Time to develop own addons for a product or not. Time to do a custom design. Time which is lost if there will never be any solution for my needs (due to that a) it's not in the official package or b) there is no addon or c) I'm not able to do it on my own) and I won't use xenforo at all.
See my point?
See, IMHO the best thing about xenforo is not what it does, but how! There are thousands of galleries out there and I hate 99,9% of them. They show pictures, right, but it's a pain to use them. So if you're saying that you plan to program a gallery - without mention the details - that's nothing which can be used by the competitors! And even if you mention some details no one knows how it will look like in the end.