well to be honest I think it's not very useful to rate traits in a vacuum. One has to look at the whole picture. Take the protective trait, for example. Look at Churchill. Imagine you could swap PRO for something else on him, would you? You probably would, I would. But then look at Mao, on him PRO makes sense, due to the Chinese UU. I would take PRO on Mao over IMP or AGG and I would consider taking it instead of CHA. Another example - Wang. PRO works very well when you have a tech lead, and Wang is a leader that makes a good turtle anyway, so I think PRO is fine on him, just as good as AGG would be.
Other examples - Elizabeth is PHI/FIN, those are two powerful traits but you can't exploit both of them to their full potential at the same time. In a vacuum, I'd say PHI beats IMP, but then I'd say that Victoria is just as good as Elizabeth, because there is at least some synergy with IMP/FIN whereas there isn't really any synergy with FIN/PHI. Or look at Pacal, his traits are amazing when you combine them with his UB and I'd say he's just as strong as Elizabeth, even though, again in a vacuum, PHI should beat EXP. Again, it's because Pacal's attributes have synergy with each other.
Another example - Ghengis vs Kublai. If I had a leader with no UU or UB and could only have one trait, I'd say CRE is just as good if not better than IMP, but again we have to look at the whole picture. I'd much rather play Ghengis than Kublai, because the Mongols are geared for war, with an early UU and a military UB. Ghengis' traits have good synergy - you have strong infantry and cavalry, giving you a strong military overall and making you less dependent on a particular strategic resource. The creative trait just doesn't make much sense with an early warfare strategy.
So, as I said, the traits are only part of the picture, you have to consider how they interact with each other and the UU/UB and starting techs to really evaluate them properly.