For those in HMA who still enjoy the challenge of city defense, but are stymied by rogue armies, try 3 artie and 5 heavy in city defense. You DO NOT need a massively superior boost advantage, just a comparable one. You WILL neutralize rogues before they can do any harm. And, if your boosts are comparable to your attacker, you'll likely be well on your way to earning a successful city defense badge. I think this setup was so successful for me, with comparable boosts, because attackers were so accustomed to an automatic rogue army victory, they either forgot how, or never learned how, to attack without rogues.
This defense also neutralizes the popular rogue army tactic of not advancing and letting city defenders march right into a rogue meat grinder. They may try that strategy, anyway, but when they realize you now have 3 trebs whacking, unchallenged, at distance and supporting 5 angry heavies, now at sword range, they won't sit and wait anymore.>
8 trebs (no rogues) defeats this, but you typically beat every other rogue army, like the popular heavy/rogues or champion/rogues (the 1st rogue army I ever saw and promptly lost too...twice--never again. You can defeat trebs/rogues, if your attacker doesn't understand how to use them.
Eventually, however, the fun of defeating the legendary rogue armies will abate...and you'll end up where we are--no city defense infrastructure wasting valuable space.