You can cellar everything. It's just that, as Mike mentions, aromatics don't really develop and improve with time in the tin like non-aromatic blends do. But if you simply want your favorite blends on-hand in the future -- and you'd like them to taste pretty much how they taste now -- then you can certainly cellar aromatics. You may notice changes in flavor after a decade or two of aging, but how these blends will or won't change will depend on each blend's specific ingredients.
To be honest, I don't think I've ever heard any aromatic smoker weigh in on the differences that age can make to a favorite blend. The idea of "cellaring" pipe tobacco is a fairly recent trend (and, for the most part, one limited to North American pipe smokers), so I'm not sure anyone's been stockpiling decades' worth of, say, MacBaren Symphony to see how it fares over any length of time.
It might be interesting to pick up an older tin of a blend you know well on eBay and do your own comparison. Of course, it won't be perfect: You'll have no way of knowing what that particular tin has been through over the course of its life. One advantage you would have over non-aromatic smokers, though, is that the same flavoring recipe has probably remained unchanged over the life of the blend. The rest of us often see blends altered slightly over time, due to leaf availability and changes in manufacturing. I'm guessing this isn't an issue that aromatic smokers have to deal with.
Bob