Since focus is so prevalent(at least in merc and rebels) I was wondering if anybody has done any math figuring out what the most efficient units to focus are? If not what are your some of your most preferred units to focus and why? What units do you avoid focusing?

Don't have the math, but I'd say in my Worlds list the Priority went like so:

Onar

Greedo/Vinny depending on opponent

Weequay

Gideon (just in case)

I agree with the above priority. Onar needs added range so he can use his awesome surges. Vinto really benefits from surges to keep himself hidden.

For Rebels, I had eSabs with targeting computer, so they were obvious go-to's. They can use the same surge ability multiple times and so excess surges don't go to waste, and they need the accuracy boost. A lot of times it will depend on the health of the enemy figures. I usually don't use a focus on Luke because his surges aren't that good and he only needs two of them, but if I need to push through more than four damage and want to one-shot something, focusing him is optimal because it gives him an entire other attack potentially. After that I go with Lando and Gideon, but mostly I just keep refocusing my Sabs.

-ryanjamal

The number one thing to consider when deciding who to focus is:

Who is in the best position to attack?

Your number 1 priority in picking a focus target should be, who am I going to attack with first? If Onar isn't going to get an attack off til halfway through round 2, he should not be your focus priority at the beginning of round 1. Try to think ahead to where you are planning on putting your figures to decide if anyone can get an attack off round 1, or at the beginning of round 2. You also don't want to waste a focus on a figure that is going to get killed before he can use it.

These are some other factors to consider:

1. Which figure benefits the most from extra surge results?

Elite Weequays have a surge for +2 dmg and a surge for pierce 1, so even if you roll 2 surges, neither of them is wasted. An elite stormtrooper has a surge for +2 dmg, but doesn't have any other damage surge abilities so you could waste a result if you roll multiple surges. Figures that have surge for +2 dmg generally get priority for focus over any other surge bonus.

2. Which figure can reroll their attack dice?

Attack dice are slightly more valuable if you have the ability to reroll them, so focusing an HK or Weequay is more valuable than focusing a Jet Trooper with no targeting computer.

3. Which figure needs a little extra range?

The extra 1-3 range from focus is invaluable for figures like Greedo and Onar. It can also help figures like elite Rangers get insane distance.

I did do the math for elite Weequays and elite Gammoreans here:

tl;dr Guards gain 1.52 damage from focus (not counting cleave). Weequays gain 1.78 damage and .22 pierce from focus.

Lastly, you should think about who your intended targets are and how much damage you need to defeat them. For example, a focused Shyla has a 78% chance to do 6 damage against a black dice, killing an elite weequay pirate in one hit. When facing Weequays, Shyla was often my number 1 priority for focus. If you're prepping for a big tournament, it is probably worth it to think about which enemies you'll see a lot of, and what are the odds of different figures killing them.