I'd be +0 on extracting common identifiers. I see a slight increase of readability, and expect a slight reduction of memory usage, and a tiny reduction in runtime. It's not really worth the effort, but I fail to see that it causes harm.

I see no point in reverting cases where this approach is already taken. I don't quite understand Victor's interest in this, either, as there are hundreds of open real bugs that could use his attention.