Here's the problem I've noticed with this cycle of getting the game out much later and more flawed. If you make people wait longer, some people will decide just not to get the game. If you release it too soon, then the game isn't perfect. If you TELL people that you're planning to release it on a certain day, then you'll have to keep pushing the date back until it's ready. CA noticed this so they decided not to give an exact date.

For the complexness of the game engine and the game itself, how good the AI really is opinion. I've been beaten by the AI on many occasions.

As for naval invasions, I'm not sure why people care so much about them. If I'm in a war with my neighbor, I would go ahead and march my army right to their capital-not sail halfway around the world to take some small island.

The average person isn't logging onto any website to voice dissatisfaction with any game, only the fans are doing that and writing lengthy posts about why they're broken.

I just found that kind of ironic
Until either mainstream reviewers start being honest, or the majority ignore them and start logging on to listen to the fans nothing will change. Since neither of these will ever happen, hype will continue to keep the Total War franchise alive.
I think the problem with the bolded statement is that people on the forums are trying to force opinions about the AI onto others. The few people I know that play this game are satisfied with it, so the only voices you usually hear on the internet are the game reviewers or the critics. The people happy with it don't care as much-They'd rather go play the game than talk about it.

As the game is right now, I would say CA did a semi-poor job on the release. It did have many bugs, but grading your own work is difficult. They've gotten lots of feedback from the players and in a few months have fixed the game up to a good shape. They're not done working and people in general are saying "okay, this game is pretty good".