Westboro is so off-the-wall, and persona non grata to EVERYONE across the political and theological spectrums, I don't think their non-existence makes much of a difference to anything, except to the relatively few unfortunates who got sued in the Phelps' system-gaming lawsuits, or had the personal displeasure of getting their loved ones' funerals picketed by the clan.
I guess that law against picketing military funerals wouldn't have been overturned by the SCOTUS, so maybe that's something. But then, that law was only passed in the first place because of the Phelps' antics, so that's basically a break-even.