More likely (in my never-humble opinion), the changes slowly accumulate until, at time point "X", we see some Homo habilis fossils.
Remember, there never were a large prehistoric population of hominids, given the sustenance-space and nutrition requirments for such omnivores before the development of agriculture. And of that small number, an even smaller number of bodies were "fortunate" enough to be in an environnment where it was possible for their remains to be preserved.
We can say that there have been a lot of links between H. sapiens and the first proto-simian, between H. sapiens and the first proto-pongids, and between H. sapiens and the first proto-hominid.
I don't think we'll ever find the missing link, because I see the entire evolution thing as a continuum rather than a step-wise set of species and geni.