Then they are not experiencing analysis paralysis, because the stances and auras are offering more decision point and more options. The entire concept of a "default stance" is farcical. Theres exactly zero difference between using the same stance for every attack and using the same at-will for every attack. Again, you're introducing more complexity in play for something that could have and should have simply been a preselected build path.
Once again, an Essentials character can declare they have a stance always on, and then rely on one single attack for the entirety of the session. It doesn't matter if they are charging, making OAs, whatever. All that matters is that they can jot down a single entry for their attack, and use it all the time, and occasionally call out "Power Strike!" for extra damage.
A pre-Essentials character, even if they choose a default At-Will, still has to deal with switching gears in situations where they can't use At-Wills - and they will tend to simply not use their Encounter or Daily powers unless you regularly prod them to do so before they decide what to do on their turn. Which, from experience, I can tell you will usually be a frustrating thing for them - feeling like another person is telling them how to play their character.
I have not run into a single person who finds the Slayer or Knight 'more complex' to use than a standard Fighter. They might be out there, I suppose. But I have encountered several folks for whom the design of the Knight actively addresses many of the issues I've seen crop up during play.
If they are indistinguishable, than what does it matter which one you choose? Yes, simple effects often look similar. If you actually have that much "analysis paralysis" you are having the same problem trying to decide whether or not actually USE your PA or BS or DS. Again, e-classes dont solve any problems, they create their own.
Except, again, the virtue of Power Strike and the like is that it is easier to prompt their use. They get to see they hit, and you can say, "Do you want to Power Strike?" It is much less intrusive, and much easier for them to reach a decision point.
If you instead stop their attack before they roll it, and say, "Hey, did you want to use an Encounter Power?" ... it usually involves them having to pause and figure out the benefits of the encounter power, and then making a decision. And feeling like you steered them to it, and being additionally disappointed if the power misses. Or already having started to roll, which means you can either back off, or you can try and have them decide after they've already rolled the dice, which adds its own complication. And, often, the result of this is that their encounter power will never get used.
I can get preferring the options of the classic system for your own use. But insisting that somehow Power Strike is more complex and adds more problems for folks as compared to the standard system... I just don't get that. What are these additional problems that they create?
Really, Is your only experience with these classes in Encounters sessions? After third level, every single one of those "easy choices" starts to come into conflict with the other aspects of the game. Once you hit paragon, the question devolves to how do I order my actions to hit this guy with one stance and end my turn in this one?
For you, perhaps. For the player who favors a simple character, once he hits Paragon, he continues to just use a default stance. Maybe his friends occasionally point out when a different one will be useful, but he can stay in his simple +damage stance all day, and be perfectly effective. He can never have a single question come up about when to switch stances.
If he's playing a PHB Fighter? By that point, he has 4 encounter powers and 3 daily powers. Which yes, he can just ignore entirely, and maybe stick with his default at-will... and he functions as a much less effective character. If he is prompted to use his encounter powers, I guarantee he is having to pause for many more decisions and considerations than the Slayer who is gleefully swinging away with a basic attack every round, using Power Strike on every attack that hits until he runs out, and whose turn takes a fraction as long as even the simplest PHB Fighter build.
"Does my default stance work?" hah, "Which of these 4 stances is best for this attack? and do I have the action to change it?" vs. "Which of these two at-wills?"
Yes, please do compare like items.
Comparing like items ignores all the important context, though. For example, the fact that many of the stances offer very simple benefits. If my stance just gives me +4 damage, I don't need to ask "Does this work" - of course it does! More damage is pretty much always effective. As such, I don't need to even bother with switching to other stances unless, as a player, I want to. And the loss in my effectiveness is generally very, very small.
The guy choosing at-wills, meanwhile, also has encounters and other options pressing upon him. And isn't likely to have At-Wills with quite as simple the benefits of the easiest stances. And needs to keep in mind that some situations won't allow those At-Wills. And the one who plays very very simply and avoids all these decisions... has a much, much bigger hit to their effectiveness.
YOU seem to believe that the only point of the e-classes is to spam the same powers over and over. Guess what? Its significantly more complex to play e-classes in that manner than it is to play 4e classes as spam-bots. Ever watch a ranger in play? Quarry, TS, TS, TS...... Rogue? Flank, Riposte, Riposte, Riposte... The e-classes are inferior at being what they were designed to be to the base classes.
How so?
If my 15th level Slayer only ever has one stance active, only ever makes basic attacks, and uses Power Strike on every hit until he runs out... that is pretty easy to do, and has a relatively small loss of effectiveness vs choosing appropriate stances every round and carefully hoarding my Power Strikes for ideal moments.
A Thief might be slightly more complicated with Tricks, but not overwhelmingly so.
A 15th level Ranger who does nothing but Twin Strike? Is losing out on a ton of effectiveness by never using encounter powers. And has a bit more to trick via Quarry, for that matter.
Same with the Rogue. Yes, you can play them by spamming a single At-Will, but handicapping them to do so doesn't really seem like they are being more effective at such things than Essentials characters who are built to spam a single attack and not cripple their effectiveness to do so.