The AI isn't an issue for me. After 4 years playing GalCiv2, I know the AI will outproduce me in the early game. If I survive the early game, I will catch up and move to the front during the midgame. I also know how the AI does it and am not interested in playing it's game in an effort to match it's early growth. The solution I found for GalCiv2, that seems to be working in FE, is large map - small number of opponents. Having some space between neighbors means you have time to explore, settle, do some research and build your strength before meeting the other factions. As I get better, I'll add more factions and increase the difficulty level but, for now - I need to figure out the monsters. They aren't just local color - they severely impact your ability to expand and force you to invest heavily in a rear guard to protect your flanks.
This is the first game I've played where it's normal to have deadly monsters camped on your doorstep at turn 1. In .915, I don't think I've ever been able to establish a second settlement without killing at least a medium monster. This takes time and money - Champions need good equipment, sometimes goodie huts are obliging, sometimes you have to buy it. Soldiers need to be trained and paid - few things will put you into the red faster than a few squads of defenders - even at a normal tax rate. If the monsters treat the AI differently than the player, it will boost the AI's ability to expand in a way that you can't compensate for by adjusting taxes.
I'm OK with tough monsters in the early game and really don't care if they leave the AI alone as long as balance is adjusted so the player has a chance to get established and grow. That should be true for any faction using default settings because those are the settings new players will use and the last thing you want is for them to get frustrated and abandon the game. On average I think late game monsters need to be tougher, I've only encountered one I couldn't handle (made the mistake of completing the Dragon's Eye quest a couple of weeks ago - imagine facing an entire flock of beasts like the one pictured above).
Speaking of the dragon, I think the developers need to make sure the monsters are appropriate for where they appear in the game and for the difficulty level the player has chosen. By all means tough - but not impossible. This is, after all a game - it's supposed to be fun!