I highly doubt that. I've only played for 2 weeks, but even if the AI has troops with six levels maxed out, it just stays in its corner and doesn't really go anywhere. So, there aren't any major problems, but towards the end of the game on TE, you might get some advantages. Maybe it just won't have enough money, after all, you need to upgrade the angels!
The main thing is to have enough money to upgrade the liches.