Well...
I'm dancing on the edge of saying too much, so I really can't go into much detail. But what I can say is this much:
I'm not interested in competing with, or trying to "steal" anything from, WotC. There's no doubt in my mind that, if/when they do versions of classes that aren't in the first PHB, they'll be excellently designed.
What I'm trying to do is twofold:
First, given that I'm designing for Necromancer, I'm trying to keep things closer to their 1E roots. Thus, if I do Class X, and WotC later does Class X, they're going to feel very different. One may be better, the other may be better, it may be an issue of taste--but they'll be different.
(The "1E feel" is also why I'm focusing primarily on classic classes, and not on newer stuff like the shadowcaster [not that I even have the rights to the shadocaster].)
Second, in those few cases where WotC has made their plans public (such as their discussion of some of the classes in the Races and Classes book), I'm deliberately trying to go in different directions. This partly ties into my first goal, as above, but there's a better reason for it.
I don't want this book to just be a "bridge" until material comes out down the road. I want it to be useful in tandem with official material. If I can accomplish everything I want to accomplish, you'll be able to use my version of Class X in the same campaign, or even the same party, as WotC's version of Class X, and while they'll both definitely be Class X, they'll also be different enough that the two players really feel like they're not stepping on each other's toes.
(And for the record, no, I do not have any inside knowledge of WotC's plans for further classes beyond the PHB. I can only judge their future plans by stuff they're already said.)