Do subjects with a missing cerebellum have a superior ability to verbalize motion sequences? Since the function of the cerebellum in patients with cerebellar hypoplasia needs to be taken over by other brain components such as the motor cortex, and since the cortex is the source of language, is it easier for these patients to verbalize their movements, i.e. are all their movements voluntary? Or does the brain stem rather replace the cerebellum's function?
I think that this question is hard to answer because there is little known about the cerebellum, and few instances of people who have been born without one. There are only 10 known cases of complete cerebellar agenesis, which can hardly be considered a sample size.

Broadly speaking, the cerebellum can be seen a 'fine tuning' device in the brain. It does not initiate movement, but rather allows movement to be fine-tuned and coordinated by receiving input from sensory systems in the spinal cord. This 'fine tuning' can apply to other areas, such as behavior, affect, and social expectations, as well as speech difficulty (often in the form of slurred speech). However, it is not well known how the cerebellum affects cognitive functions.

The 'output source' for the cerebellum is its Purkinje cells. But since Purkinje cells are found in high quantities within the cerebellum itself, they are unlikely to be of much use if the patient has no cerebellum to begin with. Therefore, it is not clear how the brain could 'replace' cerebellar function. I think that muscle memory and conscious developmental strategies are the only methods to overcome setbacks from cerebellar agenesis, and after reading a few case studies, common anecdote seemed to confirm this.

Given this information, and given the lack of evidence in any of the observed ten cases, I would conclude that it is likely that patients with a missing cerebellum do not have any sort of extraordinary ability elsewhere in the brain -- much less related to their own deficit. However, this cannot be confirmed without more case studies of cerebellar agenesis.