Dignitas - Made roster changes from Ray to Ssumday and while it's not paying off yet it's an easy choice as Ssumday is an overall better player than Ray. Same thing goes about Shrimp and Chaser.
TSM - D-Lift pretty much took a small retirement so they had no choice but to make a roster change there.
CLG - Kept the same lineup.
Echo Fox - Upgraded from KFO, Hard, Kez and BIg to Looper, Akaadian, and Gate so all upgrades as EF could only win 1 game series all last split but they already doubled that in just week 3. 1-17 last year - 2-2 this year
Immortals - The owner of IMT stated that " He would allow his team to find teams if they want" Huni left for SKT which was a better choice but for the most part IMT had no choice but to make roster moves as everyone but Pobelter left the team.
P1 - Again last split P1 was pretty much a garbage team that had 1 good game series and they won it(TSM) because of just snowballing it. Switching from Slooshi, Mash and Gate to Ryu, Arrow and Adrian is pretty much was a better choice yet again. 5-13 last year - 4-1 this year
NV and TL are the only two teams that you can say they shouldn't have made roster swaps more so NV but TL had to make roster swaps because Dardoch just couldn't get along with anyone on the team.
So for the most part the bottom teams from last split have been heavily upgraded and the higher up teams aren't so high up on the tier list so there isn't just a 3 tier A teams and 7 F tier teams so every team are going to look off because of how even they all are.