You clearly went into this too pessimistic: already expecting only a mod can save this game before buying it. Just because a mod is popular doesn't mean it will make the game more to your liking. Since you've already bought the game, why not give it a chance and play something fresh like Massilia. Just ignore the politics and diplomacy. Just do what you do in Total War games. Me I just blitz.
Given the limited development time for Rome 2, they could have easily made an amazing game if they just had everything from RTW with the updated and more realistic factions. Instead they went for a whole new experience, clearly with way too little time for their ambitions, and you won't know if you'll like it until you've tried it. Being the Rome 2 section on a Total War forum, you should expect your question to be answered with a bias. Someone even posted here the game was not worth it to him, but others who think the same simply wouldn't be in here to see your thread.
The game was twice free to play for a weekend and will probably be again yearly. I would recommend anyone else still on the fence to wait until you've really played the game.