If we decide we want this (small) backward compatibility break, to make collections.abc consistent with the other modules (except os.path), then I should mention it in the whatsnew porting section for 3.4, which is really why I opened this issue :)

I that case, IMO, the import for _collections_abc should be removed from the collections __init__ file (in 3.4.1), just to keep things tidy.