Why are the decks in Agricola called Komplex, Interactive and Easy?
My own thoughts:

Komplex Deck - Yes. The rules for all occupations and minor improvements are more complex than E-Deck. Some improvements are harder to play. For instance, the Plow(plow 3 fields a time) improvement can be played as a combo in Plow and also Sow but in Complex Deck, this is forbidden. But there are more bonus points can be collected via minors. More occupations can play additional round-action. Better oven(+5 points), better masion( +2 on stone rooms ).

Interactive Deck - There are some special minors that create additional actions allowing other players to play and the owner benefits with food, such as Tavern. Moreover, some occupations are buyers ( reed buyer, wood buyer etc.,) that can hijack other player's resource. More occupations are doing with other players instead of round-actions. 

Easy Deck - All occupations and improvements are usually doing ONE particular action. And the prerequisite for them are not as hard/complex as Komplex.

In my opinion, I would not mix all these decks. I think some occupations of E-Deck/I-Deck are significantly powerful than K-Deck. For example, Fisherman, Backer, Well builder(+Village Well + Water Carrier, this combination is the most cost-efficiency food generator, I think) etc..