Starting on p.255 some monster stat blocks have "w" or "b" indicated in their damage.  Is this defined somewhere?

It is defined somewhere. Hmmm or used to be.

B means to take the best of the two dice. I think W means to take the worst.

It should probably be added to Chapter 17, Elements of a Monster - Damage, to make it clearer though.

Might also be worth adding to Chapter 2 - Harm and Healing - Damage. Where it talks about monster damage.

But of the two areas the Chapter 17 would keep it fresh in the reader's mind as they look at the monster stats and see it pop up.

I know when I first read DW I was like "how is there no initiative for combat??". But then what rpg has initiative for social interactions?

Combat in DW seems to flow in the same way other rpgs assume you handle the PCs sitting at feast chatting with the king. It's a conversation and rolls only happen if what the players are saying triggers a mechanic(bluff, intimidation, diplomacy, etc).

It's rather interesting when you think about it the other way around. Many rpgs have a very natural flow for finding things in the world, using skills, acting socially and then they turn into a tactical tabletop miniatures game the moment you draw a sword.

wizard: I cast magic missile!
*silence*
gm: fine by me.
*silence*
wizard (feeling awkward): shouldn't I roll for this?
gm: what do you think?
wizard: I don't know, should I?
*silence*
gm: yes. I already told you like ten times. Read on your sheet: "when you unleash a spell..." you always have to roll.
wizard: oh, I got it! Let's roll then!

I don't see the player doing anything wrong with this. How this would flow with me:

wizard: I cast magic missile!
gm: Okay, roll for cast a spell.

or

wizard: I cast magic missile!
gm: Okay, you're hidden from the monster and are able to take your time with the spell. It flies out and slams into him. Roll damage.

or

wizard: I cast magic missile!
gm: The Lich sees you casting the spell and waves his hand. A shimmering shield appears around him and your missile deflects away from it and slams into the ceiling causing debris to begin to fall. What do you do?

The player initiates the action but waits to see how the world(voiced by the GM) responds to it. They can't roll dice yet because they don't know if the world is going to treat it as a move.

I read that as the +str and not the entire score. I believe when they reference the 3 letter abbreviation it's the ability score mod, while the entire name is the entire score.

Constitution + number for hp = Take the entire constitution score and add it to the base class value to get your hp.

Str + number for load = Take the bonus/penalty for str and add it to the base class value to get your max load.

Fighters start with a higher class load base as they've been trained to carry gear around while a thief with a low str is going to want to stick to lighter weapons. A thief with no bonus would have starting:

rations: 1
armor: 1
3 daggers: 0
rapier: 1

Leaving 2 left over for selecting the adventuring gear or a bow over daggers, etc.

For carrying loot out I'd figure on the players being overburdened a lot of the time but they could drop it pretty quick in a fight. Except where the thief decides to "check on the horses" while the party holds off the attacking goblins. :)

I prefer the new portrait layout. It just seems a little more standard to other rpgs and are a little easier to print out front/back.

Either way though I think the character sheets are very well done in this game. Much better than most any rpg I've read. Also I love how they package them up. The PDF is designed perfectly to do a single print run of front/back for use at the table. 2 sheets of moves to pass around, 1 sheet for each class and 1 sheet each for cleric and wizard spells. I'm guessing someone spent a lot of time moving fonts and layouts around to make it work like that. It feels like one of those things someone spent days on but is invisible enough not to overtly appreciate.

Personally I think I'd keep the damage rather low and focus on the effects. Ever seen Stardust? That movie has cool examples of witches. Mirrors shattering with shards flying everywhere, pulling out a small voodoo doll and breaking limbs/drowning the person.

Perhaps the mechanical advantage over just swinging with a staff for d6 is that these effects ignore armor and are obviously at range. Maybe have moves that allow you to bewitch more targets at once?

I guess I'm sort of a "niche" person and to me it feels like the wizard is the damage numbers niche class. 2d4 or 2d6 with the ability to maximize the spell and pump enchantments into them as damage adds.

As for what the bewitching can do, I don't know how to define that. I almost feel like there should be a list of effects you can pick and choose. Like maybe one of the effects is "can do damage", other is "can force a shape change", "can cause 1d4 buff", "can cause 1d4 debuff", etc. Where the -1d4 might be the guy puking up frogs and the +1d4 might be a love hex which inspires. The player would handle describing what he's doing.

Maybe at start you can pick 1 or 2 effects and add more as moves later on? This will build up to really big things at level 6+ when you can start to yell down a mountain.

But I don't know if that's the way to do it. My worry as a DM is it can be really hard to sort of understand what the "power level" of something is supposed to be. Vague is nice because it creates a lot of potential for flavor and creativity, but it also makes me feel like I have to balance every idea the player came up with. And as a player I'd worry that one DM would let me do everything while another one wouldn't let me do anything. Meanwhile the wizard's fireball is always 2d6 ignore armor no matter what table he plays at.

I like it. My only thing is it looks like bewitchment is a pretty core thing and there isn't a lot of guidance for how to use it in play. Given spindle and thread it can be used for damage, but should it just do the class damage?

Also I think the class could use choices in the equipment part.

Picked this up to get some ideas on how to setup DW adventures and fronts. I'm still wrapping my head around how DW does things a bit and I've been trying to fine tune my "prep for the table" methodology.

I haven't read Reach yet but I have to say that the design and layout is fantastic. Nice use of artwork, well placed, everything seems really easy to read. It's visually beautiful.

I also love the monster descriptions. The wolves "Drag you screaming into the cave" is just fantastic.