One thing about the wonder units, it really depends on what civ you are. I was duargar first game who only get rune mages and amazons and it seemed like I had none, but I reduced it to 80% of what it was and now I'm playing with the Frost giants and with all the wonder units they have I'm just overwhelmed with all the Giants, griffons, mercenaries (never got a leader in my first game) wiccans etc that I have, I haven't even really had to produce many regular units. In this case the original levels of production are probably balanced.
So it probably should be left at the original level so factions with a lot of them don't just overrun everyone. Other civs can always just build normal units or get mercenaries/red steel swordsmen/etc.
And also I do believe that the shires early attack units maybe should get +1 to def instead of atk. +1 to atk is really strong for an age 1 unit, even with the less hp. And I'm not concerned about vs me, I'm pretty sure I could overrun any ai in any diffuculty king or below and will probably get killed by them in any higher difficulty. I'm just concerned about the ai, I don't want to see one ai overrunning all the others in the first 2 ages, especially when it's on the other continent and I can't intervene.