Guests they should call

I am not listing singers here because they are always around in some way or the other...we always know their face and stories. But here are people I feel who should be called by Sony for sure:

Pre 90s:

Anandji (Kalyanji-Anandji)

Pyerelal Sharma (Laxmikant-Pyarelal)

Usha Khanna (the first female music director)

90s:

Anand-Milind (they can do an entire weekend since their father was also a music director)

Shravan Rathod

Jatin-Lalit

Dilip Sen-Sameer Sen

Viju Shah (he too can do an entire weekend, his father was Kalyanji)

Sameer Anjaan 

Raam-Laxman

Javed Akhtar

2000s onwards:

Salim-Sulaiman

Pritam

Shankar-Ehsaan-Loy

Ajay-Atul

If I had chose singers, they'd be the following since we haven't seen them on Indian TV:

KS Chitra

Poornima 

Vinod Rathod

Yesudas

Hariharan

Anuradha Paudwal

We can definitely expect Pyare Ji & Ajay - Atul. They came in last 2 seasons too.

I want them to invite Shekhar and they can do VS Special. 

Arijit Singh hardly goes anywhere so if he comes it would be great.

Chitra Ji & Kavita Krishnamurthy are in my list too.

I’d really like an Asha Bhosale special.

Other than that:

Madhuri dixit - Anil Kapoor

SRK - Kajol

Shravan (of Nadeem - Shravan fame)

Mahesh Bhatt (his movies have amazing music)

Rajesh Roshan

Chitra

Shubha Mudgal/Ila Arun 

Gulzar

Javed Akhtar

They don't even acknowledge their music team...actors make it all about themselves unlike their seniors. Why would we want that?

Not sure 100%

https://www.tellychakkar.com/tv/tv-news/indian-idol-12-have-special-episode-mothers-followed-tribute-pyarelal-sharma-210213

I won't watch the mothers special as it makes me super emotional and disturbed 

But yayy for Pyareji 

I want to see Shreya Ghoshal and Sonu Nigam on the show. They have great songs and are very professional judges. They are bound to sing live as well and that would be honey for the ears.

Definitely Shankar-Ehsaan-Loy and Salim-Sulaiman. Both of them can have special episodes. Even Vishal-Shekhar. All these music directors have great songs, and they could give constructive criticism to the contestants when they perform on their own songs.

Hariharan, chitra , Arijit Singh, kk and sukhwinder Singh