He's ignoring the middle ground, here.
The thing about a sliding scale is that there are many points between the two extremes. A system that provided only a Complex Option and a Simple Option wouldn't be able to grow and change with a player.
At each decision point, a character should be able to choose "simple" or "complex." Being locked into a choice for about two years of game time isn't great, especially as you get better and learn a system more intimately.
Perhaps you have a fighter who starts out basic, but eventually learns their abilities well, and wants to opt into more complicated powers further down the line.
Perhaps you have a wizard who is happy to have complicated illusion powers with a wealth of options, but would like simple powers when it comes to damage-dealing.
Perhaps you have a barbarian character who revels in tactical combat, but who wants to be able to grunt and be effective when out of combat.
I'm actually slightly seeing this with my Essentials-mostly game now. Level 3 seemed a little underwhelming for everyone ("I get to use my encounter power again!"), in comparison to Level 2 ("I get to choose a new power!"). They could've benefited from some scaling complexity, a sliding scale that let them take the easy option, OR, let them take another option. Without a feat tax.
One of the characters also likes burning things and going beyond his power set, so for him, a satisfyingly complex resolution mechanic for stunts is essential. Another one likes to take the diplomatic route, so having a complex interaction mechanic would make my job as DM much easier.
A class structure that had a "simple class" and a "complex class" is a step in the right direction, but it's not far enough. We need to give them the opportunity to be simple or complex as they desire at every decision point, not just once, and then they're stuck with it 'till the character bites the dust.
We also need options for "simple combat" and "complex combat," and "simple noncombat" and "complex noncombat," and, again, it needs to be a sliding scale, and maybe even different for each character, so that at each point, people are getting what they
want out of the game.
That's a taller order than "Here's some classes with a defined progression, and here's some that give you more choice!"
....though I totally agree that it's not fair to make the fighter simple always and the wizard complex always.
