That sounds backwards to me: If they have a tactical combat module, that's where the rules for tactical combat will live. If there ARE other options, they should by definition NOT be supported by the core rules. They should be supported *in* the modules.
You're missing the point. The basic game needs to be built to take these modules and use them.
You can't just pile rules on top of each other, the base game does need to
support the other, modular content, if the developers are serious about making those modules, and various combinations of modules, viable.
If a class is to be expanded by a module, then the base class needs to not only be balanced against the add-on version of the class, but the base class also needs a structure which allows people playing the class to easily upgrade it to the module version if they choose to.
And there are second-order interactions. If the class has feats in the base game, how do those feats relate to the more complex-module version of the class? Are they worthless for it? Do they have unintended effects?
Not only that, but even if the balance and design is up to snuff, the system needs to be somewhat transparent, at least clear enough with the rules, that players and DMs considering such a change can understand better what it means and what it's result is likely to be.
I get that some people don't care about this stuff, or disagree, but as a fan of 4e and other similar games, if they genuinly want me as a customer, then these are the kinds of things they need to do. Otherwise, they're not offering the product they advertised, because I'm not in some tiny minority of 4e players, here.
This isn't even close to an Alpha. You won't see an Alpha for another year. At the moment, they'll still just playing around with the design.
So they're publicly announcing, and releasing to bloggers and conventions, a
pre-alpha build of their game?