Try 'Boss'.
I loved The Wire, but Boss is better!
no chance.
the only thing that comes close to the wire or even beats it is deadwood.
Boss has nowhere near the same character development. in fact the characters are rather lame tbh.
boardwalk empire is good but nowhere near as good as:
deadwood (amazing character development)
the wire (similar quality of character development as above)
sopranos (pretty good character development)
first half of seasons of lost
first half of seasons of the shield
game of thrones (very good character development)
spartacus
rome
brotherhood is similar to boardwalk empire (worth looking into) irish americans who are corrupt and have power, 2 brothers one a criminal and the other a politician.
deadwood would be my first choice though, then the wire (simply because the quality of the wire, picture wise is bad, its only 4:3 and grainy imo)