Personally, I feel the Roman UU is how UUs should be. Since the 2.08 patch (and warlords expansion), UU have sucked all around. They're not significantly better than their replacement (except for the Aztecs: theirs is worse).
A UU should be a period-dominating unit since they're the height of effective units!
After all, if you let the English get Redcoats, you deserve everything you get. The same should go for all the other conquering empires. The UU should be something that the best way to counter is to advance your techs past it.
I agree. Not that every UU sucks since the 2.08 patch, but UU's should indeed be period dominating units. As an opponent without a good counter you should be left to trying to survive in that period of time. Of course, the UU's were probably nerfed because the AI can't effectively (ab)use them theirselves, so it'd be better to focus more on AI capabilities than on nerfing UU's.