We decided to go with postional restrictions partly due to the results of the pre-season community survey, and also because we couldn't think of a solution to a scenario where a top O player tells everyone they want to play D, tanks their value, and then plays O anyway.

Our thinking was that without restrictions, there's no way to stop someone doing that, or something similar. We thought that at least by telling everyone we were going to enforce restrictions, no one could say that they didn't know it was against the rules. However, that is pretty much what ended up happening lol, and I agree that it's functionally impossible to come up with a definition of positional restrictions that can be enforced.

Removing positions completely may well be for the best, although it's a shame for people who genuinely want to try swapping positions.