Ah, the age old question. There are some old threads about this topic that contain some useful opinions. Some think original is the only way to go and others see no harm at all in restoring it, especially if it is being done by the hall of famer that made the cue. Perhaps it comes down to which is worth more: a 70% all original or a 100% fully restored one. Everyone is sort of speculating on how this affects the value of cues. Cars it seems, are always better all original. Paintings, on the other hand, are restored all the time (i.e. renaissance).
I don't really have an answer. I know I talked to Ernie about it once and he said some collectors prefer an original but as soon as they get it they have it restored before putting it in their collection.
One thing though, a restore is a little different than what it sounds like you are talking about. For instance if I had an old 60's Gina Titleist with square cut corners on the windows I sure wouldn't have Ernie change them to mitered corners just because he now does it that way. That kind of stuff I would leave original. I'm thinking more of a re-finish, restoring the condition of the cue. Changing things like that is not really a restoration, by definition.
On the one hand, it is only original once. On the other hand, once the maker retires you have foregone the best method of having it restored. But there more flaws it has (parts not fitting properly etc) the more I would be inclined to have it worked on.
I'd like to see some of the high end dealers and collectors around here chime in on this one.