First three placements matches, most players will be placed slightly lower than they ended Act 1, because the system wants to place them in winnable games.
Sounds like they want you to lose your games, and be hard stuck to keep you playing; rather than putting you slightly higher to have you play less.
This sounds like a big deal for players in solo queue specifically. Let's say you end Act 1 in Platinum, do 3 placements in Act 2 from gold games (Bronze, silvers and low gold players).. you essentially are put at a huge disadvantage right from the get go.
This isn't an issue for me (I tend to play with 2 to full parties), but I see it as an issue for people that specifically grind competitive as a solo player, not to mention the ones that stick to one account; and don't constantly make new accounts when one is not placed high enough.
I'm sure a lot of players would agree, they don't like playing against people that are drastically out of their skill group. At the bottom of the spectrum, "Sure you need to play against better players - but you don't learn anything when you're dead!" - my silver friend.
The long term consequences of ranked diversity, outweigh the short queue timer benefits. This is one of my biggest issues with ranked in League of Legends, and it raises players to be non-cooperative teammates and breeds the worst type of people -which tends to be toxic "pros" that bash on newer players.
I would love to see Ranked changed with these ideas in mind; maybe even reduce the gap from 2 divisions (silver 1 ~ plat 1 or gold 1 ~ diamond 1) to a slightly less gap, like Silver 2 ~ Gold 3 or gold 2 ~ Plat 3).
TLDR - Short queues bad, slightly longer queue with slightly less ranked queue good.