If you're gonna make a sniper champion, at least give the impression that they are somewhat balanced.
I don't mean to come in and sound mean but...Here, I'll just give you a short review. And by short I mean long.
[Passive] - Focus: This little niche of focusing has already been done with Ashe. Granted, the ability is called Ranger's Focus, but it fits the idea of a ranged champion focusing on their shot or their next attack. Also, I can understand her having a higher base range than other ranged champions; I put in a similar concept a while back, but the range she gets is just really really REALLY insane. Plus she has at least 10% armor pen at level one. Tanks couldn't touch her unless she wanted them to.
[Q] - Staccato: The passive MS is actually...well I was gonna say balanced, but then I noticed that she's stickier than Ashe (who's passive is literally a slow) even with her not auto attacking anyone. She consumes her stacks of Focus upon attacking, so if you abuse the 800+ range she has on her fully charged AA you just start sprinting towards someone at Mach 5 for 2 seconds. Or you could just run away with it.
The active is...at early ranks it's decently ok, but 2 auto attacks at 800 range is still quite a bit. At rank 5 you have 6 autos at 800+ range that have your passive armor pen and are 100% faster than your normal attack speed. It's like a free Jhin ult, except all of them can crit.
[W] - In My Sights: At this point, Freya has 3 passives in which one of them is overloaded. And that's her base passive. Ok, time to do another one.
This passive is busted, and I'll explain why: When you're bot lane, or even within any of the other lanes, you'll most likely keep someone within your sight range for at least 5 seconds. That means you'll be able to get one of you little 800 range auto attacks on someone, and it will deal a bunch of bonus damage that scales. Now I am a bit confused; are you making it scale with HER maximum health or HER ENEMY'S? Because one of those makes it broken, and one of those makes it worthless. I'll let you do the math there.
Also yay, an ability that deals magic damage to a target on a physical damage champion. This would be fine if she either A) Had an ability that legit scaled with AP (which she has none of) or B) had another ability that did magic damage. Sadly, she does not, meaning your DPS won't suffer very much against targets who build armor to counter her insane range and other physical damage abilities.
Oh and don't even get me started on the active. Not only does this fantastically stupid ability have 2000 range which, let me remind you is about two full turret ranges, but it also deals 100% of your bonus AD (which pre-items is only ok) plus high base damage and refunds 80% of the cooldown if it hits a champion. If this ability pierces minions it hits you'd pretty much always have this super poke up, and even if it didn't you'd still be able to just move around a minion wave and get a snipe off. This does more damage than Jhin's W, technically scales harder, and also has the ability to be cast repeatedly at almost no cost.
[E] - Dance of Death: You talk nowhere at all about an ammunition mechanic. Where is this coming from? I feel like this champion tries far to hard to be a Jhin clone than just being unique, which is what you should strive to create with a champion concept; something unique. I'm just gonna get to reviewing this ability.
It has a cooldown of 3 seconds at all ranks, meaning she's stickier than literally every other champion in League of Legends. She doesn't even have to be; just reset the cooldown by grappling to walls and you can abuse her range to poke people down. But let's say, for some gods forsaken reason you choose to hit a champion with this; It's a Quinn E clone (she vaults off of who she hits and lands quite the distance back) except it does more damage and slows who she hits. Even if this "ammo recharge" mechanic deals specifically with the damage part, you could easily abuse the 3 SECOND COOLDOWN AT ALL RANKS to vault off of anyone jumping on you, or just grapple to terrain and repeat until safely away.
The concept is interesting, but it's also broken beyond all belief. If you want to make Freya at all playable in a balanced way, I highly recommend giving her kit a complete revamp with a full explanation behind everything AND severe toning down of numbers. And things that she can do to utterly destroy her opponents.
[R] - Hail of Bullets: The range is alright for once. I no longer feel like you're just playing American Sniper simulator with Freya on this. However, that is the only good thing I've found for this ability. At first glance, it looks a bit like it is balanced. 100 - 250 damage isn't super busted and it isn't fantastic either, and 1 second of being untargetable is pretty ok. But then I notice the scaling; 200% of AD. And if she's got full focus she gains the passive armor pen which, as I'll remind you, increases by 5% every 25 AD. At 150-ish AD she has 30% armor pen. So at rank 2 with 150-ish AD, and this is if you aren't stupidly ahead of your lane opponent at this point, the ult deals 475 physical damage to enemies within 1200 units of Freya. Plus if you use your Q to automatically gain full focus, you have 30% armor pen. So you use this as an alternative to escaping by instead dealing a ton of damage to people who want to kill you.
Seems legit.
OVERVIEW
I think Freya could be ok. It's certainly possible to take a broken champion concept and turn it into a balanced one; I've done it before. But you first have to admit that the concept is broken in its current form, which from what I can see you clearly have not done yet. I'm not trying to be mean with the things I say; word choice helps to add to the urgency and altitude of which some of these things are unbalanced. But I did come here with the intent to give you a review. So now that it is over, I think I'll be taking my leave. Best of luck to you on the Fields of Justice.