A few points have changed since release. The ai spended much less gold on navies, so they had more stacks on land. One time one ai had 6-7 Stacks(with experinced units and many ronins) at the front, you won't find similar Situations now. Autoresolve also has been changed, so it's easier. You could have a 3:2 calculated sthrengh on the field. Now its a cheap win, earlier it was a devasting defeat (only on legendary).
You won't find a challange at realm divide. Earlier it was interresting, but now it could count as a big battle, when the ai comes with 2 stacks.
And btw, now you can have up to 40 units on the battlefield(earlier it was 20), so it's much easier now.