I am VERY HAPPY with what WotC is doing here. The Battle Master is looking like tons of fun, and the Warrior too, and everybody will be able to choose his own complexity comfort zone : a clear win !
Exception based design is a tricky tool, and I agree the game has to rely on a clear and efficient core engine. Concerning 5e, the engine is here (ability checks), but the systematic use of a d20 makes it a bit whacky (perfect for combat, too unreliable for mundane checks IMHO). Some say "Basic combat maneuvers" should be accessible to any character. Yay ! But I certainly wouldn't consider disarming someone as a "basic maneuver" : it should be simulated by some grappling rules making it very difficult... or abstracted as a critical hit or as narrating the final blow (for me, abstract is ad-hoc abstract favoring a smooth integration of story and mechanics, not some primacy of mechanics over narration).
The 4th edition engine seems as suited for running 1 vs 1 encounters than chess or Blood Bowl : it sucks badly, and I am happy to get a leaner engine able to handle some naturalistic framing of combat. Yes, two people having an argument should be allowed to draw weapons in a featureless back alley without causing a system failure !