I've been playing Snowdown ARURF ever since it was available, and I can say that it needs more than serious balancing. Some champions are impossible to beat, especially with the restricted champion pool. I'm gonna list all the "broken" champions that I can think of that completely ruin the game.
1- We're in urf, which means most of the time, fighting goes on less than a few seconds, where as his ultimate provides 5 seconds of invincibility. With the CDR, his ult is always UP, which means he is unkillable.
2- You cannot catch a Tryndamere because his E has basically 1 seconds cooldown. There's around 2 or three champs that can catch him, but would die doing so (Fizz, LeBlanc).
3- 90% of the Tryndameres I've played against go hybrid, which means the AP scaling allows them for a huge amount of healing, coupled with his ultimate, makes him impossible to kill. Along with the 30% crit chance he gets and the increased atk spd bonus frim urf, he can 2 shot you along the way
There's nothing special to say about her other than the sheer amount of damage she outputs is simply contradictory with the tankiness she can build. 4000 HP along with 2 Qs to kill you, and if you manage to win the fight a bit, she simply can spam her E until you're as low as her, which makes low HP Irelia even more dangerous. Again, unless all of your team has cc all over the place, you will simply not be able to fight her at all.
Another champion that you cannot kill. You simply max W, you become untargetable most of the fight, and since you get hit by a lot of spells here and there, your passive is always UP, always. One game we were all 5 of us on Maokai, it took us 28 seconds to kill him, do you realize how that is to kill him ? Along with the fact that the chain from the W root and the Q knockup, if a Maokai catches you, you cannot escape no matter what you do. Plus AOE stuns like Veigar are absolutely useless since your W makes you untargetable, making you unable to get stunned and get over those barriers.
As I'm sure you would expect it, Jax is in the list. No matter the build path you choose, Jax always destroys you. Even if he goes 0/10 at min, as long as he gets 2 items, you are basically doomed, whether it is AP, AD, Bruiser, or Hybrid. His W can be activated before using his Q, so landing the Q applies both the W and Q dmg, resulting in 70% of your HP gone, requiring him only to do that again. Along with his ultimate giving him more resistances than you, giving him always an advantage over you. His E is also very hard to counter, but not required for him to kill you in an instant.
This one is not about it being OP, but rather the fact that his fling is just way too annoying. You cannot do anything about it. If he manages to fling you, you are basically dead. Even if he goes full tank, all he needs is someone behind him to finish you off. You flashed ? Too bad, I'll fling you again. Plus with the Predator keystone, you can't escape from him, whether it is early or late game. You can use as much spells as you want, he will always be there to fling you in his team. The cooldown on that spell is way too low.
I might have forgotten some champs here and there, if so, remind me down below and I'll add them. I loved URF and ARURF, I had so much fun in both of those gamemodes, but Snowdown ARURF is just ruined by these. I've said it in multiple posts, RIOT should implement a balancing mechanic where the 2 teams have an equal value of champs ("Example" Red: 2 OP, 2 normal, 1 weak ; Blue: 2 OP, 2 normal, 1 weak). This restricted champion pool just makes some champions OP, and others shit. I understand the concept of Christmas and Winter being linked to this, but it shouldn't be to the detriment of balance.
And lastly thank you for reading, and I hope RIOT will read this, and if so reply to me with their view on the situation.