This is one of those things where the decision needs to be made between realism and fun...
PS2 Spin was most certainly NOT realistic in any shape way or form... but it sure was fun
Really IMO, the spin move should be done in place for the most part. Very little ground should be covered horizontally with it. In the PS2 game you could probably go to the left almost 3 yards, which is ridiculous.
Once again, I'd have to probably point to the 2k series ... that's a pretty well done spin move for the most part.
In any event, the spin move should not be a tool used to change directions unrealistically. Should just be there to help you break out of a tackle, or to perform just before a defender dives at you so you can spin off of them.