i agree. I think its gotten worse now.

The alternative would have been "Can I play now, daddy?" difficulty mode where you could just steamroll the AI. It is unfortunately not possible to really program the AI to use better tactics in battle (well, there is a trick with a save game edit, that enables 41 units in armies. This makes the AI stop doing some of the most egregious stupidities in battle. Still wont be very clever though), neither is it possible to make it learn from its mistakes and adapt; it is not reacting dynamically from one battle to the next, and the save game edit for 41 units wont change that either. This makes is very vulnerable to the player exploiting it's weaknesses because it never learns. Once you learn to employ good tactics (mainly effective flanking) you'll get 1:10 loss/kill ratios in almost every battle. What makes it interesting is that different factions can offer different weaknesses and different effective tactics due to their units different strengths/weaknesses and different army compositions.

Only way to offset this huge advantage that the intelligent player has over the not so intelligent AI, is too allow the AI to cheat with artificial bonuses to income and by adding, in my opinion, interesting new challenges for the player like the population and supply system. The AI cant understand population and supply system so it wont affect them. Well, for supply there can be SOME effect at times for the AI, but it is very limited compared to the player, to avoid the AI losing all of its troops to attrition because it doesnt understand or even know it is happening.

Carthage is scripted to declare war on Rome at certain points/criteria is fulfilled and from there on afaik and in my experience scripted to not accept peace deals. Although the punic was was had periods of peace in between Rome and Carthage this would be very very difficult to script properly, I dont know if it would be possible.

So yes, Carthage is OP in the beginning, and the waves of stacks send against Rome in Sicily or Magna Graecia, is to actually make it a real challenge for you. You can only overcome this by building up a stronger economy allowing you to raise more armies/fleets with better and more expensive units AND also employ good tactics in battle to minimize your losses; finally enabling you to counterattack and take Carthage.