Much better. However, I would have chosen another order. Instead of making the division of offensive, defensive, balanced and within each category dividing in tiers, I would have made the first division in tiers, and then within each tier divide in offensive, defensive and balanced cores.
Ubers
Offensive
Defensive
Balanced
OU
Offensive
Defensive
Balanced
UU
Offensive
Defensive
Balanced
...
The idea is the following. Suppose that I want to build a team for OU and I have no idea where to start from. I want to check all the OU cores and then choose the one I prefer. I still don't know for sure if I want to play an offensive or defensive core, but what I know for sure is that I want to play OU. So, I want to have all the OU cores together in order to check them all, and not have any other core around as I'm not interested in it.
Ubers:
OU:
RU: