I believe that good martial artists will work on their weaknesses regarding what they and their art lack. It is that simple. In 1993, the world of martial arts got a wake up call. They found out that reverse punches and ridge hands were not enough. They found out high flashy kicks and holding your hands at your waist was not enough. Most importantly, they found if you don't know how to grapple or at least have basic sprawl and position knowledge, anyone with adequate grappling will kick your aszz!!
As I mentioned, the first UFC happened way back in 1993, eighteen years ago. The sport of mixed martial arts has come a long way as have the emergences of grappling tournaments to the mainstream. So it really isn't that hard to figure out, the information is there and has been there for a very long time.
Skills negate skills, and all aspects of fighting should be trained if one is to be a competent fighter. Also, the days of pure anything (striker, grappler) are over, at least for those wanting to be relevant to today's standards.
"The hero and the coward both feel the same thing, but the hero projects his fear onto his opponent while the coward runs. 'Fear'. It's the same thing, but it's what you do with it that matters". -Cus D'Amato