Despite eagerness to learn, play, and do a bit of homebrewing, I'm still fairly new to some respects of D&D, especially in regards to what ultimately makes a class powerful. As I'm exploring this more and more I've noticed what I'm sure many have noticed, namely that the classes that are considered the most powerful from core are those with a strong spell selection (Wizard, Druid), while the least impressive ones are those that focus purely on martial ability (Monk, Fighter).
So, I have a question for those more veteran than I: is this just the inherent nature of martial classes? Are they always to be less impressive, and often less enjoyable, due to their melee focus?
Many of the fixes or better options for Monk or Fighter that I have seen appear to amount to giving them something akin to a spell selection, like martial art manuevers, or simply providing a spellsword. Should I draw the conclusion that if one wants to pick or make a good class that can stand on par with a Wizard or Druid that it needs something similar to spellcasting?