Admittedly, the main effort so far in reducing complexity seems to be the deletion of explanatory aspects of the GPLv3 to make it shorter. However it does seem safe to say that CopyLeft.next represents a practical effort to test Fontana's theories of how to make the GPL licenses more attractive.
Fontana is not automatically opposed to BSD-style licenses, suggesting in his talk that FOSS would benefit from a greater use of them in order to evaluate their strengths and weaknesses. But, unsurprisingly, he believes that any serious weakening of the GPL would be harmful to free software. In Copyleft.next, I suspect, we see his efforts to anticipate and prevent that weakening.
Whether Copyleft.next will amount to anything is impossible to predict right now. For now, the real value of the news is that it might give Fontana's analysis of the current state of FOSS licenses more attention.
Not that Fontana's views are definitive. As Bradley Kuhn points out in the podcast that broadcast Fontana's talk, another reason for any decline in the GPL might be that younger developers, having come of age in a period in which code was routinely released, may under-estimate the importance of GPL licenses in creating that expectation.
In other words, like people who grew up without the threat of smallpox or measles, perhaps they don't appreciate the importance of vaccination.
Other critiques are no doubt possible. However, while Fontana's analysis may not be perfect, it is one of the few efforts to explore the question of the GPL's current status from an impartial, evidence-based perspective. Although it may not offer a complete picture, it does seem to provide a more accurate analysis than other efforts to approach the same topic.
Even if Copyleft.next eventually contributes nothing to actual licensing, the observations it seems to be based upon are worth hearing. They reflect one of the saner efforts to evaluate the current state of free licenses, and deserve to more widely known, regardless of whether Copyleft.next itself succeeds.