Questions about tags

Hello.  I have some questions about weapon tags.  I am going to be GMing a game soon.  It seems like it will have many characters in it.  One is a channeler (which gets to choose 2 tags for abilities among a list) others are more traditional fighters.

I have read several guides here about running combats and how you want to get players doing more involved things than just going for damage.  That sounds exciting.  I just have some questions about it and game balance.

Suppose you have (either the same character having 2 diff possibilities for attacks or two different characters):

Person A: Sword that does 1d6 damage with the force tag.
Person B: Sword that does 2d6 damage.

So Person A does their attack with the force sword, does their 1d6 damage, and knocks the opponent back a little.

Now Person B says that they "lunge at the enemy with their sword while hooking their foot behind the enemy so as to knock them down."  So if successful they seem to do 2d6 damage plus get a knockdown.

Suppose there is a third person:

Person C: Has a Flaming sword that does 1d6 damage.

They do an attack that does 1d6 damage plus some fire damage and/or fire effects or DOT.

Now Person B sees that and when they attack they say they "Lunge at the enemy with their sword while hooking their foot behind the enemy so as to knock them down and while simultaneously bringing their other hand (1H sword and other hand carries a torch) with a torch down on the enemy so as to light them on fire."  So they might--if successful--have a burning, knocked down enemy who they have lit on fire.

You get the essential question I am asking here.  Powergamers love to powergame.  How do you deal with players who powergame abilities over other players if these powergamers are proficient in using the fiction to describe what they are doing?  I am just asking for general suggestions here.

I can see, for example, requiring extra dex checks for coordination and/or discern realities checks to look for openings, etc.

Note to my players:  No :D I am not looking at anyone in particular.  I am just looking for general advice.

Suppose you have (either the same character having 2 diff possibilities for attacks or two different characters):

Person A: Sword that does 1d6 damage with the force tag.
Person B: Sword that does 2d6 damage.

So Person A does their attack with the force sword, does their 1d6 damage, and knocks the opponent back a little.

Now Person B says that they "lunge at the enemy with their sword while hooking their foot behind the enemy so as to knock them down."  So if successful they seem to do 2d6 damage plus get a knockdown.

So!
In my opinion, Person B is actually doing two actions here, and they need to choose which to resolve first.
I would say the the lunge (part 1) is a hack and slash, but they'll probably need to defy danger to perform the second portion (the trip).
Even though it's described as one action, really two things are going on, so there's double risk (whereas Person A gets this as an automatic effect).

Suppose there is a third person:

Person C: Has a Flaming sword that does 1d6 damage.

They do an attack that does 1d6 damage plus some fire damage and/or fire effects or DOT.

Now Person B sees that and when they attack they say they "Lunge at the enemy with their sword while hooking their foot behind the enemy so as to knock them down and while simultaneously bringing their other hand (1H sword and other hand carries a torch) with a torch down on the enemy so as to light them on fire."  So they might--if successful--have a burning, knocked down enemy who they have lit on fire.

Here again, I would require at least two rolls (hack + slash and defy danger) to attack and knock the person down. Then the torch part...

... maybe the enemy has a free hand, so I "tell them the dangers then ask"... "The soldier fell, but he's on his back; as you bring the torch down, there's a good chance he'll swat it away - or, worse, grab onto you and pull you down as well. What do you do?"... this will probably lead to a defy danger.

... maybe it is hard to fight with both a torch and sword (actively fight, not just hold it), unless they're trained in two-weapon fighting... so, maybe on a failed roll or 7-9 they will drop the torch, burn themselves, etc... this is a danger not faced by the player with the flaming sword (remember, fictional positioning works both ways)

So, you are looking at 2-3 rolls plus additional fictional dangers.
The guy who just attacks could get attacked back.
The guy who tries to attack, trip, and burn could... get attacked back, fall down, open himself to an additional attack, drop his torch, burn himself.

All other things being equal, you should fairly reward players who make strong use of fictional positioning, as that is what makes the whole game sing.

- Alex

Now Person B says that they "lunge at the enemy with their sword while hooking their foot behind the enemy so as to knock them down."  So if successful they seem to do 2d6 damage plus get a knockdown.

Person B: I lunge at the enemy with my sword while hooking my foot behind them to knock them down?
GM: okay, well you're at sword range now and you'll need to close the distance. So are you jumping past their blade to get inside with your foot, or is your plan to lunge with your sword and as they reel back, sweep their leg out?
Person B: Can I get past their guard without getting hurt?
GM: Sure, you'll be defying danger using your Dex. We'll see how that goes?
Person B: no. I lunge with my sword (Hack and Slash: 10).
GM: Your sword bites into his shoulder and he screams in rage as he staggers under the blow taking 1D6 damage.
Person B: I sweep his leg out!
GM: Awesome. You get in close and hook your foot behind his, pushing we all your might. Roll Defy Danger using Strength.

Or, whatever your fiction demands...