I would agree that lacking either of those things would cause the problem I described, but in this case we have both of those.
Most recently, I was the one joining a project after its incipient stage, so I was not the big picture guy, but the big picture guy chose not to establish any kind of patterns or standards so when others started joining the project--even with an understanding of how it should work--suddenly the app had a lot more functionality but it all performed terribly because of a lack of uniformity in design. Code review helps, but ultimately because there are no established patterns there is no justification for telling someone a task should be implemented differently, right? The only solution I can see is to establish that justification by trying to get the big picture guy on board with a massive refactor to establish some standards.
Most recently, I was the one joining a project after its incipient stage, so I was not the big picture guy, but the big picture guy chose not to establish any kind of patterns or standards so when others started joining the project--even with an understanding of how it should work--suddenly the app had a lot more functionality but it all performed terribly because of a lack of uniformity in design. Code review helps, but ultimately because there are no established patterns there is no justification for telling someone a task should be implemented differently, right? The only solution I can see is to establish that justification by trying to get the big picture guy on board with a massive refactor to establish some standards.