This is what happened to me with the new winter map:
* The cursor is not at the right position. It's broken! When I point my cursor right above a minion in reality I'm not focusing him! I would say that the cursor is shifted on the right by 1 cm. Playing is impossible
* Even if I've a decent PC, my FPS are tremendously low but the real issue is that it doesn't matter what settings I use. From low to high I always get the same amount of FPS. Before you ask no, I'm not using the feature that locks FPS. It's like I'm playing Crysis at max settings
* I lost all settings. Keyboard, mouse, GUI, all sliders, checkboxes... everything!
* The game in general is sloppy. It all moves like there's glue everywhere on the map. I can't explain it but it's frustrating and unplayable
* I have a 34" 21:9. It sucks. I tried on 21.5" at full HD. It still sucks
I never had such issues with winter map but now it's ridiculous. I can't play this way. I will simply waste my time and ruin the game for my team mates. I played just one game and enemy support had the same issue. There's clearly something wrong with the new map and I have no intention to play ranked just to get rid of it.