Apologies I know this was originally a 'from white' perspective, but if I want to vary from QID against 3. Nf3 then I enjoy the Blumenfeld gambit rather than a pure-Benoni approach. Partly because the idea is completely different to the Indian defences - occupy the centre as black rather than control from afar. This can throw white, especially if they know you are usually an Indian player!
Well, the Blumenfeld has been mostly refuted, and if White knows the complications, Black can't hope for more than equality. But the thing is, the gambit is pretty rare, so chances are White doesn't know what's going on.
At the very mediocre level I play at in willing to back on them not knowing the sharpest lines as white 😆! Doesn't Caruana still employ it on occasion though?
QGD is my new favourite after years of diminishing returns from the Modern Benoni, which more and more people have studied these days.
So what you suggest is like a fake Nimzo? And go for either D5 or QIndian. But don't those get boring? Nimzo is more excitement, yes?
Well, against 3. Nf3 I'd say Black's best chances to win are to go into the Bogo with 3... Bb4 or transpose into a Semi-Slav with 3... d5 and an eventual ...c6. Queen's Indian is a solid choice, acceptable if you want a draw.
But if you were playing aggressively for a win, you wouldn't go for the Nimzo, because you'd know of the options with 3.Nf3? You'd play the Grunfeld or King's Indian, wouldn't you?
I'd describe the Nimzo-Indian as a method for Black to play for a win without taking excessive risks, unlike the Indian defenses with 2.. g6 (Grunfeld or King's Indian).