Is Intelligent Design a serious alternative to evolutionary biology?

The Quarterly Review of Biology has an article What Is Wrong With Intelligent Design? by Elliott Sober

This article reviews two standard criticisms of creationism/intelligent design (ID): it is unfalsifiable, and it is refuted by the many imperfect adaptations found in nature. Problems with both criticisms are discussed. A conception of testability is described that avoids the defects in Karl Popper's falsifiability criterion. Although ID comes in multiple forms, which call for different criticisms, it emerges that ID fails to constitute a serious alternative to evolutionary theory.

Sober explains the principles of testability which could apply to Intelligent Design, and end up concluding

It is one thing for a version of ID to have observational consequences, something else for it to have observational consequences that differ from those of a theory with which it competes. The mini-ID claim that an intelligent designer made the vertebrate eye entails that vertebrates have eyes, but that does not permit it to be tested against alternative explanations of why vertebrates have eyes. When scientific theories compete with each other, the usual pattern is that independently attested auxiliary propositions allow the theories to make predictions that disagree with each other. No such auxiliary propositions allow mini-ID to do this.

It is easy enough to construct a version of ID that accommodates a set of observations already known, but it also is easy to construct a version of ID that conflicts with what we have already observed. Neither undertaking results in substantive science, nor is there any point in constructing a version of ID that is so minimalistic that it fails to say much of anything about what we observe. In all its forms, ID fails to constitute a serious alternative to evolutionary theory.

In other words, there is no real theory of Intelligent Design, hence it cannot be an alternative to evolutionary theory.

Of course, the Discovery Institute is not happy about the article, and have responded: What is Wrong with Sober’s Attack on ID? (Part I): Defining ID and its Historical Origins

I see that this is part I, so hopefully they'll eventually write something dealing with the actual content of Sober's article, and not just try to argue that someone used the words "Intelligent Design" before it became necessary to try to cloak Creationism as such.
Of course, given the fact that Sober is quite right, I don't expect this to be the case - expect more nitpicking and no addressing of the actual content.