League is full of too many players who have managed to climb in the past, but don't currently belong where they are. People who "coast along" season by season, just doing their placements and barely enough games to keep them from decaying. It's full of too many players who "got lucky" and managed to get carried through their placement games. The game is full of too many players who pay someone else to boost them, or players who have "friends" who are playing on their account and getting them to ranks they do not belong at. These things are literally visible at every tier in the game.
I'm by no means the greatest player on earth, but it doesn't take a rocket scientist to see that the people who are truly gifted don't have trouble climbing up, and they don't hate it either. These players make alternate accounts almost every season just to prove to themselves that they can actually win against anyone. Hard resetting the ladder only affects players who might not actually belong where they are, and I really fail to see why the ladder is not HARD RESET every single season.
The whole idea behind "climbing" is to earn rewards, so why are players above high gold / platinum given a free pass every single season for the next season's rewards? Just because a player is able to climb up the previous season doesn't mean they should be automatically handed free rewards for the next season by simply playing their placements. Playing one season and reaching Diamond+ shouldn't automatically hand you a free trip to Platinum every single year either.
Over 9 years in the making of nothing except soft resets and this is what we have. A game where your rank means nearly nothing unless you are at the very top of the ladder. Soft resets are far too forgiving for people who don't actively even play the game. Don't get me wrong, I'm not a fan of taking anything away from someone who deserves it, but you can play the game, watch live streams, and see that there are quite some number of players who don't belong where they are ranked. The design of ranked doesn't address that because it's way too hard to demote out of a tier, and soft resets make it so players never demote too far from where they were the previous year even if they lose every single match.
10th Anniversary is a good way to give everyone a "fresh start". I mean, the ladder is already wrecked at this point, it won't get any worse by throwing everyone back to square one next season.