But that was always the choice in older editions:
be a fighter and be mediocre all the day, or be a cleric and be great in one encounter per day.
4e originally had the "elegantly balanced" approach: every class is equally useful at each encounter.
4e Essentials+core allows fighters that are equally good over the course of a day, and about equally good in each encounter... just play a knight and a normal fighter in a game of 4e and you see how good it works.
And it is not just extra work. You can build a fighter that has some cool tricks in his sleeve and can do things the other one can only dream of. But you also have to work more during the game to make most out of your abilities.
Good thing: your more/less efficiency delta is only about 20%... which is no problem in the actual game.
The most basic fighter, seems well enough. The only thing you need to run it are few lines of text, and guidelines like those on page 42 in 4e.
It only does not work that easily in 4e to incorporate this page, because of the "elegant balance"... You are drawn into this isolated combat, because everything works so well together and you don´t need to improvise. Also it is difficult to allow cools stunts as a DM, because you must be careful not to make those stunts better as powers.