For me, M2TW and RTW are not complex at all compared to Shogun 2. Unlike S2TW they have many realism issues and they are hardcore linear - same factions go through same stuff every time you play. Auto-calc is heavily screwed up in both the titles. Diplomacy is non-existant, and every AI eventually ends up blocking your port.

The most interesting TW titles for me are MTW and S2TW. The new Shogun really hit the spot - the only thing I really think is imbalanced is the Realm divide, which is imba in the way all factions start hating you and that it's never triggered by AI. The unpredictability of MTW and the years of perfection of S2TW are what I really like!