I think it depends on the type of work that is done in the extra time. If it's only polishing and adding content, I also think it can only get better.Normally, more time to work on something leads to better quality, unless the organization of the project is bad (so it's not always true, for sure). It may not be good enough in some cases, but that doesn't mean the extra time didn't improve it.
But if there are significant design decisions being made the game could obviously become worse. Perhaps you meant this with organization.