Actually I like the trade ship mechanics, I find it complements the trade aspect, however I completly agree that If I can avoid dealing with naval warfare the game feels much more relaxing, I do suspect tho that it is due to the fact that I don't understand naval warfare in this game.
My strat is usually build light ships and transport (5-10-25 depending on needs and FL), when u go to war hide the navy in a port with fort, when u are at peace steal the trade of the others with light ships.
Avoiding the mental gymnastic that maintaining a big heavy fleet (except late game where you swim in cash) or even worse the correct proportion between galleys/heavy ships is something that I find relaxing.