A way to give a striker the ability to control one enemy in limited circumstances! A neat ability, and I completely support spreading the roles around a bit, but the fact that the same character could have shot his opponent in the face makes him a striker.
I'm not so sure about that. Strikers are fine-point damage machines. If the archer is like most of D&D history, arrows will never do the kind of damage that melee can do. But they could easily carry rider effects on the arrows, and we definitely have precedence for turning one arrow into a massive rain of them (which could all share an effect).
I don't think an archer would be a good fit for a Striker at all. A rogue can sneak attack. A warlock can eldritch blast. A measly 1d8+Strength can't compare to EITHER of those in damage capacity, and it seems more likely to give archers other stuff to do with their arrows than to significantly buff up their arrow damage to rival sneak attacks and eldritch blasts.
A way to give a defender a controller type power. But since such a class is almost guaranteed to have the physical stats necessary to grapple, pin, and kill the enemy instead of throwing them, the class is going to be more innately a defender than a controller.
Grapple? Pin? That's definately controller territory. A defender doesn't mess with the enemies directly, doesn't manipulate their actions, they stand there, they soak up damage, they maybe manage to keep things within their reach, but they're not about crippling the enemy. That's controller territory, I believe. Defender territory, like was said about the fighter: "one you're in their reach, good luck leaving it!"
This is controllerish. But wouldn't it be more logical to make the stinkbombs purchasable items, available to anyone?
The old "unless you're trained to use this, it has a chance to go off in your hands" would be my way of protecting that niche.
I like this ability. I don't know why its a controller ability. It seems well suited for a striker, because it lets you get behind enemies and stab them in the spleen.
It would work well for a striker, too. But whereas a striker would follow it up with a bucket o' damage, a controller would follow it up by saying "COME AND GET ME!" and leading the enemies away.
A neat way to give a defender or a striker the ability to control a smidgen once in a while.
Again, a defender doesn't want people outside of their reach. A controller's job is to place the enemies where they will be the least effective. The controller kicks the enemy into the defender's reach, where the defender keeps him.
Which was showing how a class built mostly on controller abilities can still have a diversity. Perhaps instead of flanking, the target looses an action as they look for whatever is behind them. That'd be more controller-ish.
Don't know why this would be controller typed.
Another that would work well for a striker, but basically showing how a melee-based character can still have a lot of battlefield mobility, enabling them to get to where they need to control.
Basically, a defender with a lot of battlefield mobility would make a very good controller, because his reach would be an area of control, and if he could move the space of his reach every round, he can affect the whole battlefield.
When people try to create a martial controller, they're going to most likely end up with a melee bruiser that naturally fills a striker or defender position, but who happens to have one, maybe two controller type abilities that affect small numbers of foes and which have limited range. Meanwhile the wizard is going to be splitting the battlefield with walls of ice, and granting his allies the ability to fly over lava.
And the Wuxia will be creating chasms, and the Yo-Yo master will be creating swaths of destruction, and the Battle Trickster will be scattering caltrops and the Archer will be disarming and the Swashbuckler will be "pulling" creatures in a duel...
I think we should give up trying to create a martial controller, and instead focus on creating ways to spread the roles around a bit.
I think you've given too much "controller" territory to the "defender." So this is more about lacking a clear definition of these roles than about actually not being able to fill one of them.