The impact of the fall of the Berlin Wall itself is very limited.  The fall of the Berlin Wall was merely a symptom of the demise of communism, not a cause.  The real impact came from the fall of communism.

The fall of communism completely changed the world.  Of course, it affected Germany by reunifying the country.  However, its impact has been at least as great on the rest of the world.  We no longer live in a world where there are two superpowers constantly poised to go to war with one another.  In this way, we are all safer and more secure than we were during the Cold War.