Frankly, I like a little imbalance in the game. And besides, what of the other leaders? Victoria, say, with the Imp/Fin combo. Or Catherine with Cre/Imp.
Personally, I'd rather see the UU, UB, and starting techs balance. Then, assign the traits as best as possible, trying to keep a little with the historical personalities that we are representing. Then, let the cards fall as they may. Persia and Rome may be a little bit stronger, but that's not a major issue--sometimes, I want a challenging civ, and if I'm going up a difficulty level, I may want a strong civ. Or, at least I'm sure there are people out there who may appreciate this.
Needless to say. Ever played with the balanced resources option?.. guess not. It will be too dull of a game if there wasn't the variety and shuffleness there is in the best game ever. Besides, there are so many facts going on on a gameset (terrain, strategic/general resources, neighbours), all to cope with the leader traits and your personal strategy.
Indulge me:
This same night i went to a friend's place to continue with one "challenging' MP game. This Kublai guy had more tech than us, more land, and of course a much larger army. All of a suden we (playing as Ramses) managed to exchange chemistry for paper, astronomy, education and the printing press, plus some 2000 in gold. Immediately upgrading that fleet of caravels to frigates and vanishing one long kept GG into an admiral warlord, thus giving one aditional promotion to our now brand new ten large frigates fleet, was the only way of regaining the edge in a naval warfare we were about to dramatically loose and sufer. Conclusion, our two and three times promoted vessels beat down some five mongol frigates in their's rapidly reached shore and anchored about another 10 cargo galleons within a city's port ready to launch a full scale invasion over Egypt the turn before.
Of course, i won't argue this imperialistic trait to be as easy to use as financial or agressive (that's to be honest why so many players find them the goodest), but it is for sure as exploitable as any other. I believe though that in lower speed mods like marathon (were all tech/civics/GP's advance is slower relatively to units movement and cultural expansion amongst other issues) this trait is particularly better. Financial is a more balanced trait here (tile yield is more balanced with other systems), but that would be a completely new issue for discussion.. right.
Keep in mind that the benefit of having settlers and workers earlier is exponential. Nevertheless it is both game appealing and relevant for imp to have espionage bonnuses in BtS. As well as protective should have some bonnus in counterespionage. Surely we are going to find either of these, if not both.