Maximus being a douchebag farmer

I don't really care for most of historical inaccuracies in this movie, but one thing that's important to the plot bothers me.

So apparently all Maximus wants is to go back to his farm and raise crops with his family. The idea seems fit for Medieval soldier of lowest rank, who would be taken in the army against his will. All he wants is to serve well, so that his master would allow him to go back.

But a Roman general is a person of high class and a free man. His profession is war, not farming. If he wanted to be a farmer, why didn't he? If he wanted to earn an estate and farming land through fighting, he would have had slaves work there and had an income from it, while remaining a general. The fact that slaves are supposed to work on his land is carefully hidden from the audience. Surely his land is fairly expanse for a man of his stature. He is not going to handle it alone. Not only it's impossible, but also embarrassing.

His wish to not be involved in politics is also rather difficult to chew. Him being a top military leader and a friend to the emperor makes him a more important politician than any senator.

Overall the writers of Gladiator are trying to push us the idea of Maximus being a simple man and some kind of a christian, but that's not really believable (they're trying the same with Marcus Aurelius though). It wouldn't be too difficult to write him up a proper Roman while keeping revenge motivation intact.