The pluses:
1. Lata was the first singer to have really brought an aura of respectability to the often-tainted film music- medium. She was acclaimed for her virtuosity by practically every stalwart of Indian music from Bade Ghulam Ali Khan to Pandit Ravishankar.
2. Her voice was the major factor in the success of almost all the leading Hindi film- music composers of the Golden Era. Her songs are associated with practically every major cinematic milestone in Hindi cinema.
3. Lata has always maintained a certain dignity and decorum in her song selection. She is a shining example of class and culture overcoming the crass crudity - often touted as an essential ingredient for commercial success. "She could sing all types of songs but she defined her own limits. She was the only singer who knew up to what point she should go and at what point she should stop. That's why she remained the real melody queen." These are Manna Dey's sincere compliments!
4. She adapted so well to the changing tastes of audiences over five decades without ever really sacrificing the essential Indian-ness of her music.
The minuses
1. The stranglehold exerted by her voice over the, composers' minds limited the opportunities for the rest. Geeta Dutt, Asha Bhosle, Suman Kalyanpur or Vani Jayram- no one could really get over this handicap.
2. Her many tiffs with co-artists like Sachin Dev Burman, C. Ramchandra and Mohammed Rafi denied the listeners of many probable gems. (But it also proved to be a boon in disguise for competitors!)
3. The progressive ageing of her vocals over the last two decades might not have affected her phenomenal ability to deliver hits but the ethereal, aesthetic charm which was the essence of her singing has been a casualty in the process.
The verdict
To reach a verdict, I suggest a simple litmus test. Take almost any major musical maestro on the Hindi film music scene and just consider his music without Lata. See how hollow and incomplete it sounds.
She has been the life-line of Hindi film music for over 50 years. No doubt, she is the greatest!