While I can see how some people may find spec groups to be restricting, I found it to be one of the best parts of Shadowbane. Spec groups were designed around builds, and yes, some guilds and eventually the server popuation would run pretty much the same thing, but there is more detail to this depiction than may be evident.
First, spec groups are the result of a good deal of testing, experimentation and theorycraft. This is a fantastic and enjoyable process, and while it is true that it eventually produces what is most effective in general, all-purpose use, it does more than that.
That brings me to the second point - the discovery of unusual, highly specialized off-spec builds, a natural consequence of the process of theorycrafting and designing spec groups. In some cases, you will come up with something that is the direct opposite in nature of the cookie-cutter builds and their effects on combat that the OP is concerned about. In this regard, sometimes a spec group will be highly vulnerable to these counter-meta builds, and I personally took advantage of this many times in SB.
Third, no matter what mechanics you put in place, efficiency and effectiveness will always be selected for when it comes to force composition, and if you are not doing this, then you are failing in your first and primary task as a battle commander. Spec groups may seem boring to some, but you don't throw down your gun and pick up an atlatl just so you can be different.
Now all of that said, while I do not feel that you can nor should code out spec groups, I do think that it is necessary to provide a system which has enough diversity and sufficiently rich mechanics to not only allow for but require diversity of builds. Shadowbane was a good example in this regard, as even though certain things at different eras of the game became established spec, game elements like resist jewelry, shrine boons and siege spires provided some tools that could be leveraged against a particular spec. In the context of Crowfall, my hope and expectation is that this will be the case to an even greater degree, because CF has a few tools and mechanics that SB did not - and the current state of the game during this test is not the final form of that.
As we get closer and closer to the final form the race and class combinations will take in release, as more and more fixes occur, we are already seeing an increase in the number of viable classes and builds, and this is already impacting what we are seeing on the field. I know our think-tank comes up with something new, and viable, every week - and there is one build in particular than hasn't been used in combat simply because it is so damn good and we don't want people copying it...
In short, while I agree the problem the OP describes CAN exist, I do not think it DOES exist in Crowfall.