Given the sort of excitement the USA is enduring now from the executive, boring could be considered a Very Good Thing and a compliment. . .
Now this one is really interesting. Founder of the Republic, despoiler of Kings, promulgator of the oath never to allow a king again in Rome. Normally I'd say the fact that most of what we 'know' of his life may be Legend, since there are really no records from his time, would make him a marginal choice, but since we've got Gilgamesh, Dido and Tomyris, 'legendary' or even completely fictional is obviously not an obstacle!
Aside from tossing the king and his family and setting up an Aristocratic Oligarchy (Called a Republic, but one carefully managed to ensure that the top families could outvote the other 80 - 90% of the population) and prohibiting any more kings, though, what to do for Attributes or Uniques? One possibility is a 'negative' Unique: Rome under him could never choose any kind of Monarchial Government. Another possibility would be to give Rome under him a Bonus for choosing any kind of Republic.
Another point is that he lived before the Legion evolved into its well-known form: based on archeological and linguistic evidence, in his time it was a simple decimal-based phalanx of spearmen supplemented by some Nobles on horseback. Come to think of it, though, a possible Unique would be to allow Spearmen to be Upgraded to Legions (happened after his time, but would neatly show the transition Very Early in the Republic he founded).
Finally, he survived under the king Before the Revolution by feigning dull-wittedness ("Brutus" means dim or dull) so perhaps Rome under him could only be played by the AI?