I think this KBC with SRK will also be a Hit like AB's take earlier.
Because both are king in their given circumstances & possess different styles.
Also we should not forget that young generation (so called 'Gen Y') will go for SRK now. this same happened in case of DON, 'Gen Y' like SRK's DON very much & it was a hit to a extent because of that. This means both of them have different sets of Audience & Fans.
Now, just have to wait & watch how SRK fairs in the show.