The mid-80s being the most important time period in wrestling is debatable, to say the least. After his dad's death from cancer in 1984 Vince, Jr. began the destruction of the territories of Vince, Sr.'s pals/cronies in earnest. So, from the point of view of the spread of the WWWF and monopolization of the industry under the WWF/WWE banner the mid-80s definitely had a historic significance.
However, there have been a number of very important periods in wrestling history that one could argue trump the mid-80s. For example, we could go back to 1908 when Frank Gotch upset George Hackenschmidt and brought the undisputed World Heavyweight Championship to the United States. That was followed by the Gotch/Hackenschmidt rematch in the newly constructed Comiskey Park that drew a crowd of 30,000 - a record that held for 50 years until Rogers/O'Connor on June 30, 1961 in the same venue.
During this period the "chain" style of wrestling was introduced from India to the West and wrestling began moving away from the traditional "static" style practiced in the U.S. and Europe. This was a major milestone in the history of professional wrestling.
However, in my opinion, the Golden Age of Wrestling which is gauged from about 1950 to 1965 trumps the mid-80s as the most important period in the game's history. The Golden Age coincided with the advent and rise of television. Television was a perfect venue for professional wrestling which had been transformed into a faster paced, more cohesive display of athleticism by Buddy Rogers' introduction of "sequencing" which replaced the "chain." George Wagner's persona brought more color to the game which now fit with television like a hand in a glove.
At the time the lack of other viable TV programming was a big plus and gave wrestling a chance to be broadcast into the living rooms of millions of families who would otherwise never have seen a wrestling match!
Kayfabe was at its heyday, sports sections of newspapers reported pro wrestling on an equal footing with other sports, and many people did not suspend disbelief - they actually believed pro-wrestling was for real!
For better or worse, The Golden Age of Wrestling layed the foundation for what has followed today. The mid-80s were a result of that legacy.
- Mike