Some background of why this would be wanted would be very useful.
I have seen people want to use Tumble Through to move into an enemy's space and then back into their original location. The background being that they are playing a Swashbuckler and want to gain panache without having to end up in a bad position on the opposite side of the enemy.
But I can't think of any scenario where using Step and not moving would be anything other than a complete waste of an action. You don't have to spend all of your actions of your turn if you don't want to. You can just no-op one of them.
Edit: The only possibilities I can come up with are subordinate action Step actions for an activity. But I can't think of one off-hand that has a mandatory Step subordinate action.
Are there any Step-Strike actions? That’s the only case I see. Step-Stride or Stride-Step resolve by just Striding five feet less.
Catfolk: Light Paws for reference of the Step-Stride or Stride-Step activity.
There is also Drifter's Juke but the Step actions are explicitly optional.
Fire Kineticist Impulse, Kindle Inner Flame Stance:
Ah. Now that makes sense.
OK. I'm going to talk my way through this...
On one hand, the lore and narrative description of the ability invokes ideas of the movement itself being what causes the damage increase. So it seems like you would need to change position in order to stoke the flames.
However, Stand Up is also a move action and it definitely doesn't change your location. Crawl is also a move action and doesn't really add to the description of quick movement that would stoke flames.
In an open field or reasonably sized room the question is pretty much moot. You can usually find a decent location to Step to in order to trigger the damage boost.
The only times it would be a question or concern would be if you are in a narrow hallway or a very tactically good position that you want to continue occupying.
You could always use Stride to move out of the position and then back into it. That would be a move action - one that you wouldn't get for free. It would provoke reactions. But it would result in you remaining in that location (barring any really strange readied actions that the GM decides to set up for the sole malicious purpose of neutralizing this tactic).
But is that actually necessary and balanced? In the open field scenario, it is expected that the free action Step is available and would trigger the bonus fire damage. The feat and impulse is balanced with that in mind as the intended use case.
So yes. In this particular case, I would allow using the granted free action Step to be used even if you have nowhere that you want to move to in order to gain the bonus fire damage from the Kindle Inner Flames ability.
I would say no, you need to move through the kinetic aura to pick up the fire effect to use it for attacks. It requires movement, not just the free step, so it seems to be saying you have to gather the fire to you by moving through it.
It requires movement, not just the free step, so it seems to be saying you have to gather the fire to you by moving through it.
And Stand from prone qualifies, but moving around in the 5 foot square doesn't?
I would say yes. You simply move 1-4 feet, instead of the 5 feet required to get to the next space.
No one would tell you "you cannot Stride less than your full speed." I fail to see how this would be any different.
2.5 feet forth, and 2.5 feet back.
2.5 feet forth, and 2.5 feet back.Again, that would be a houserule since grid movement specifically is made in 5ft increments.
I'm not debating if one wants to allow it as purely a houserule, I find that those kind of arguments are best left for each individual table.
I'm just pointing out that the RAW here requires a "move action" quite clearly worded as such. "Step into same place" is not one currently existing.
It is my opinion, drawing from other extremely similar impulses, that this is neither a mistake, nor a trivial requirement. And as such, at least in my games, I would enforce it.
Which is a reasonable stance to take on the matter.
But I find it to be a balance problem that you are forbidding something that allows consistent use of the ability in all cases solely for the stance of rules pedantry.