Also, Universal currently lacks the superhero comic book franchise that 20th Century Fox, Sony, Disney, and Warner Bros. are cranking out, which is why Universal desperately tries to have the Dark Universe to mirror of that of the Avengers, which failed. Comcast buying 20th Century Fox along with X-Men and Fantastic Four would boost Universal and put the company in the superhero business. With Fox producing Deadpool II and the potential Dr. Doom and Mulitple Man movies, these franchises would easily incorporate into Universal's portfolio.
In regard that it doesn't mean much for theme parks, it has a LOT of potentials, considering Universal Orlando purchased additional lands near the Orange County Convention Center. Having Fox assets with many popular franchises would be a boost for Universal Parks & Resorts and Universal doesn't have to worry about licensing and copyrights. Planete of the Apes attraction, possibly a ride based on the Fantastic Four and X-Men (although Universal has the theme park rights, having Universal gaining X-Men and F4 rights would clearly boost its staggering MSHI), Aliens ride, etc. All that is needed for Site B so Universal wouldn't have to worry about licensing other companies' properties. It would also affect the plans for Universal Studios Hollywood, Universal Studios Japan, Universal Studios Singapore, and the upcoming Universal Studios Beijing. Fox assets would greatly boost the park. On the side note, Disney World has the theme park rights to Avatar and therefore Universal Orlando is not allowed to use Avatar in the same way Disney World isn't allowed to use certain Marvel characters.