[Critias]

I can tell you that there is (at least) one more Way Of the ... book in the works, that I know of.  Or, at least, I think I can (without it counting as an NDA violation).

I'm pretty sure Jason has said the same think, so you should be save

Yeah, that tends to be my earmark.  "Jason said more Way of _____ books are coming," and "Jason said there's fiction in the works," and that sort of thing.  I figure once he says it, I'm fair game to disseminate the information, or play parrot, or what-have-you.

But anyways, yeah.  There's at least one other Way of book, that I know of, being worked on.  Two, I think, but one I know of for quite certain.

[Henker]

It is a GM decision to choose what he wants to have in his game, but I definitely like "way of the adept".
From my point of view however it is more a book to be used by a GM to introduce new misteries or "ways" to his players who play physical adepts.
 

[JustADude]

It is a GM decision to choose what he wants to have in his game, but I definitely like "way of the adept".

Speaking of GM decisions... is WotA legal for Missions?

[Critias]

It is a GM decision to choose what he wants to have in his game, but I definitely like "way of the adept".

Speaking of GM decisions... is WotA legal for Missions?

Unfortunately, no.  As part of the Shadowrun Options line (even as, currently, the only part of said line) it's a set of optional rules, and as such it's currently not allowed for Missions games. 

When I stat up Missions NPCs I still like to add some (optional) stats for them if they happen to be adepts, but that's just because I like the rules and want to have 'em there for folks that might use 'em in a home game.