They did seem to skip some trait combos due to overpoweredness. Philosophical/Industrious was avoided. I think it holds true for Industrious/Charismatic in Warlords.
Cyrus has a great combo of traits but I'm not that big a fan of his UB. Huayna Capac has a great combo of traits as well and a great UB but his UU is too early if you're in a large map.
It seems that the earlier the UB, the better it is, while UUs are best in midgame. I haven't found out a single civ who has a great combo of traits while having a great UB and UU, so they did some balancing there. Of course, I could be missing something.
Cyrus has a great combo of traits but I'm not that big a fan of his UB. Huayna Capac has a great combo of traits as well and a great UB but his UU is too early if you're in a large map.
It seems that the earlier the UB, the better it is, while UUs are best in midgame. I haven't found out a single civ who has a great combo of traits while having a great UB and UU, so they did some balancing there. Of course, I could be missing something.