After playing with Lou Chuans in the new campaign, I found that the ship is much more capable of fighting other ships than Cannon Galleons. Despite being siege ships, Lou Chuans and Dromons are nowhere near as helpless as Cannon Galleons against other ships. Sure, they aren’t meant to be the best at naval combat, but they are much better than generic Cannon Galleons in this area, which makes Cannon Galleons feel more niche.
The Spanish Cannon Galleon is obviously an exception.
Sure, Cannon Galleons have longer range, but this is only really useful against maybe Teuton Castles or Turk/Korean Towers. I would rather have Cannon Galleons be as good against ships as these new siege ships are.