The January developer update for Dead By Daylight is a hefty one, though I doubt it'll be enough to satisfy the kind of Dead By Daylight players with 1,000 hours logged and a negative review on Steam. Among its most significant changes are a revamped HUD, which shows character portraits as well as a hook counter next to player names. The killer can also see hook progress as well, and the whole UI is scalable.
Matchmaking ratings will return "in the near future" after having been tested in 2020, and skill-based matchmaking will be tested again. Once that system's been finalized, ranks will no longer be used for matchmaking and will instead become part of a new reward system: "Each month, everyone will be given Bloodpoints based on the highest rank they’ve reached and then be reset to rank 20."
Animations will change because, as the developers put it, Dead By Daylight is moving "towards a more realistic direction". It's a purely cosmetic change, with no impact on movement speed or acceleration.
Other changes include graphical updates for the Gideon Meat Plant and the Crotus Prenn Asylum, and changes for the Clown including a throwable antidote that releases speed-boosting gas, which can affect both the killer and survivors if they risk getting close enough to stand in the cloud. Other tweaks affect traps, the Wraith's invisibility, the Undying hex, and more. You can find out about those in the full developer update.