Dilbar mere is a Kishore Kumar song, and the voice quality of Kishore da and Sonu is very different... the timbre is totally different.
Undoubtedly Emon sung Dilbar mere beautifully, but it was a different type of singer singing the song. Our ears have adapted itself to hear a Kishore song in a kishore like voice. His voice is different and we believe he sang it differently. Morover, Dilbar mere is a more open throat singing song, whereas kal ho and ho is more soft (in terms of layman language - not using technical sound terms) song.... and therefore, the treatment has to be different.
I do not fully agree with Javed Akhthar but I will agree with one thing - When repeatedly everyone kept telling him that he had a sonu hang over and he had a choice to shut up his detractors by selecting a song which was not originally sung by Sonu, he choose a Sonu song, only adding fuel to the fire. This is what happened when Anu Malik chided him on his over confidence. It took him two to three weeks to rectify his public persona... Thankfully, he got Dilbar mere to redeem himself.
But at the end of the day, he sang flawlessly
