In the case of the double leg takedown, adding the called shot difficulty is enough, I'd go ahead and make the enemy prone if he succeeds. It's definitely not out of line considering he could spend 3 Adv for the same result (Or worse, the GM Screen recommends picking an effect out of the 'Critical Injury Table'.

Making a called shot (With 2 Neg die) would actually decrease the chances of knocking someone down in this case!

In general I would say that in this system you roll the dice and then narrate the effect. In most other systems you state your full intention, calculate the difficulty, then roll the dice to see if you succeed. So EotE is sort of "backwards".

So you state I am attacking the Bith. You build your dice pool and roll. You describe the result (spending Triumph/Advantage) as "I do a double leg takedown and the Bith is now prone".

I understand very well how this dice system works. Making an unarmed attack normally and hoping for the 2 Advantages needed to call it a double leg takedown is one way of doing things, but certainly not the only way. The called shot rules on page 201 make this the sort of thing you can decide on before making your Brawl check. This helps you perform the technique without needing 2 Advantages for unarmed's Knockown quality (thus saving potential Advantages for other stuff) at the price of making the roll a bit more difficult.

On a more practical note, having a description of an intended attack before any dice are rolled does wonders when it comes time to cinematically describe the end results.

Called Shots rule? More like the I-Aim-At-The-Guy's-Jet-Pack rule!

Called Shots rule? More like the I-Aim-At-The-Guy's-Jet-Pack rule!

Exactly! (Or, alternatively, the power supply on a heavy repeating blaster.)

It sounds as though have already decided how you plan to handle this situation. Certainly spending one or two Aim maneuvers and then declaring a brawl attack as an attempt at a double leg takedown is a valid approach. If the attack succeeds the target is now Prone in addition to damage.

There may be times when the attacker does not want to sacrifice the maneuver(s) spent aiming. In those cases I would allow then to declare the attempt, but require Advantage and/or Triumph to achieve the desired effect.

Called shots do raise the specter of characters always declaring head shots, or melee attacks on the head/neck for one shot kills. I do see some potential for abuse.

However called shots also allow for cool things like shooting the blast door controls on the opposite side of the hangar bay and thus dropping the blast doors in the face of the advancing would be reinforcing Stormtroopers. Again, this effect could also be achieved by spending Advantage/Triumph. Multiple routes to the same end. Something I like very much about these rules is their flexibility. No, but... Yes, and... Yes, but...

Luckily for me my players have yet to discover called shots.

It was that **** rancor battle with the thermal detonator and vibro-spears lol. It didn't help that one of the players took a sword to the head the scene beforehand, permanently lowering his Intellect by 1, meaning he spent the fight rolepaying his character as a drooling simpleton. It was all quite hilarious, but it also means the idea of called shots is burned in their brains. (Apparently a couple of them have even used this fight to brag to some Pathfinder players Edge's battle system.)

Yeah, I can see how that fight would be influential. Clever players, but how do you get them to unlearn it?