Personally I find the single player of any Total War game to be absolutely awful and boring, and only care about there being a competitive multiplayer. It is a sub par strategy game that if you play it well, you end up auto resolving your battles because you have a stupid advantage and its not worth the load times, or if you have strong armies to fight, you end up going against a horrible AI that will charge your perfect defense positions or not respond to basic maneuvers like flanking light infantry or cavalry. It doesn't really matter what the setting is, if the gameplay is repetitive, lacks depth, and features trash AI.
However add a human commander and balanced army sizes/strength on each side, remove the Paradox Game 4 Babies campaign, and suddenly the game fills its own unique niche, an RTS with no stupid base building or "macro" and is just about battlefield tactics, using your armies strengths and exploiting your opponents weaknesses. This is why I feel Shogun 2 is by far the best game of the series, because it doesn't have a worthless shit multiplayer matchmaking mode and isn't all about guns blobs and artillery like Empire/Napoleon. Its the only reason I'm looking forward to Rome. I don't know how anyone can play these games single player and actually enjoy themselves either. It sucks!