There's a time for variety--it's after the mastery of the fundamentals. The fundamentals prime you for longevity rather than the short term performance.
Yes, we should learn always, and remain students of our bodies and seek out learning more complexity in our movement. However, adding variety to avoid boredom and learning a new skill [and so mylinating new paths in the brain] are entirely different behaviors.
"Before I learned the art, a punch was just a punch, and a kick, just a kick.
After I learned the art, a punch was no longer a punch, a kick, no longer a kick.
Now that I understand the art, a punch is just a punch and a kick is just a kick."
-- Bruce Lee
What have you simplified, distilled in your practice? What parts of your practice are as basic as it gets?