I play everything from Monarch to Deity, and I definitely think some traits vary greatly in usefulness depending on level; for me the most extreme case is Industrious though.
On Monarch, I get all the wonders I want anyway; IND is good but I would just as happily spam wonders with a PHI leader to increase the rewards.
On Emperor and Immortal, it's my favourite trait by far. Without it, wonders are costly and might cause me to neglect other, more important stuff like expanding and defending adequatey.
I'll still spend more early hammers on wonders than anything else, so it is still superior to other production-oriented traits like Imperialistic or Expansive. Also, Forges are an expensive building that is very very beneficial to have early on; I still have enough leeway to build them over the usual high priorities and it gives me a considerable edge.
On Deity, I can't get any decent use out of the trait. I kill my economy all the time just grabbing the land I need to make a comeback, eliminating or at least crippling a rival or two becomes a high priority and I simply have too many other things to do.
I'll occasionally build one or two wonders (prime suspects: Great Wall, Oracle, Great Lighthouse) but the trait isn't doing me a fat lot of good. I can't rely on an Oracle Slingshot to get me Metal casting, and I might not have the luxury to build forges anyway (cultural pressure, crippling maintenance costs, whatever).
On Deity, I prefer traits that I don't need to actively leverage because I'm not exactly in control most of the time.