For instance: I always though the optional Move "Things are tough" was a little off.

It is of note that Vincent says right in the AW rulebook that that "move" was included because playtest groups wanted it, but that it's not recommended because it doesn't add anything other than hassle.  Apocalypse World makes no claim to model degree of difficulty in any way other than through the fiction, so that particular move is a spectacularly bad example - it's not central to how the game functions.

Pretty much the entire point of that 'optional' move is that it is terrible and nobody should use it. It's like a way to tell if somebody has understood the game, or if they are still struggling to understand how fiction-first play works.

I absolutely agree. And, I have yet to find a justifiable reason to use this "move" in any of my games. My point was that "logically" it fit the established mechanics better as a tag rather than "move":

To me, it made more since to stick these mechanics in as optional tags: Stupid-easy (+3), Easy (+1), Difficult (-1), Crazy-Difficult (-3). At least that's how I do it in my AW Hack.

If you play the game with the situational fiction in mind, you don't need these tags at all.

Yeah, I think we game geeks have a tendency to want to believe our beloved games have consistent systems, even when we have to push a square peg in a round hole. AW is awesome, but not perfect or always logically consistent (sorry Vincent) :-P

Anytime you make a game with it's own unique engine, you're just going to have to break the mold here and there to make things work.

To me, they seem like a design compromise. The ideal philosophy is that Moves are suppose to be charged situations that the characters find themselves in. You roll because what happens next can greatly affect the narrative. However, you also want improvements that will introduce situations. Now you have a choice, keep things simple and call all of them "Moves" (even though they are different mechanics) or make the rules complicated to follow by introducing a more comprehensive nomenclature (these are "Moves" these are "Enhancements" these are "Move Alterations" these are Improvements", etc.).

Again, the game is not perfect, but you can't fault Vincent for being human (awesome though he is (please don't kick me from forum)).

For instance: I always though the optional Move "Things are tough" was a little off.

"Things are tough. Whenever a players’ character makes a move, the MC judges it normal, difficult, or crazy difficult. If it’s difficult, the player takes -1 to the roll. If it’s crazy difficult, the player takes -2 to the roll."

To me, it made more since to stick these mechanics in as optional tags: Stupid-easy (+3), Easy (+1), Difficult (-1), Crazy-Difficult (-3). At least that's how I do it in my AW Hack.