Rebel guidance.

[ReluctantSamurai]

Shouldn't Carthago be one of the richest city of the game? At least in RTW it was so... why I get just 549 from it?

The number you see on the campaign map does not represent the true income of a city. It's a reflection of how your total costs are divided up between all of your cities. To see the true income of a city you have to open the city information screen, then go to the income/trade screen (third button down on the right side page). There you will see all the individual trade routes both land and sea, where they go, and how much they are making. All of that is totaled up and that is the true income of a city. That Carthage is still in the positive despite all the overall deductions,is an indicator that it's making quite a lot of money (most large cities usually show a negative number).

I lost about 200000 within 15 turns.

You probably have too much army upkeep compared to your income. A good rule of thumb is that army upkeep + wages (family members, agents) should not exceed 1/2 of your total income. If the treasury gets into the millions of denarii, one can obviously afford much more than 50%. Conversely, a treasury well below 100k should carry much less than 50%.

Quality of buildings may have some effect on revolts, but not all.

I should have been more clear in stating that barracks and bonus buildings increase the chances for a higher quality revolt. It still comes down to probability in the end.