Too sad that Nisha really has to go after 4 years but I think there's a better opportunity that has been offered to him. If Nisha goes to Team Liquid then he's still with a good team.
Edit: Team Secret already announced Boom as their mid player. --> https://twitter.com/teamsecret/status/1598663300983984128
and here's the article from Team Secret webpage : https://teamsecret.gg/blogs/dota-2/welcome-boom
I just hope Boom will be able to fill up the shoe that Nisha left in Team Secret. Like you said, 4 years is a long time playing with the team. There will be a lot of adjustments especially for Boom to fit the gaming style of the 4 Team Secret left in the team.
Is it confirmed that Nisha will be playing for team Liquid? First it was Topson, now Nisha. Both players are mid laners so Micke has to adjust to become the offlaner or Nisha will transition to carry offlaner. Whateve position he transition to, hopefully he fits well to his new team.
Puppey and his teammates will adjust easily like how they've adjusted so quick during the LCQ.
As for Nisha, not yet confirmed that he'll play for Team Liquid but we have that feeling that his choice to leave Team Secret, he's going to another strong team that he know of to sign him we just have to wait for further official announcement.
I remember when Nisha was firstly announced playing with Team Secret and watched him with his past team, Kinguin.
On the other teams, Alliance announced their roster.
Pos 2: Chyuan
Pos 3: s4
Pos 4: ponlo
Pos 5: Handsken
Source --> https://liquipedia.net/dota2/Alliance
3 players from Sweden and first time to see they'll play with 2 SEA players, wishing them well.