I don't feel that closing the linkwheel as a whole is particularly damaging. It would be computationally intensive for Google to work out something was amiss over the whole wheel, as it would have to create a database of your whole link structure and run a detection algorithm on it.
I have many effective wheels which were closed from day 1. On the whole, it is not very important if you close the wheel or not, as the flow of link juice around the wheel, i.e. the supposed cumulative juice effect, cannot usually occurr due to inefficiencies in juice evaporation and leakage.