Complexity in move-set must also be decreased.

No? Increase time between moves that are difficult to dodge or parry, reduce damage that those moves deal. Difficulty is reduced while complexity remains the same.

Also in the game world enemy placement and quantity must be adjusted to lower dificulty. Otherwise it'll be, mostly, just as hard

I've never met anyone who actually has trouble with normal enemies in these games, it's always bosses that give us trouble. But also, see my first point.