Bachchan and Bachchan's real-life relationship translates to excellent chemistry on screen, and they're wonderful in Sarkar. Unfortunately, a great cast (kudos to Kay Kay and Tanisha for roles well played) can't always compensate for dodgy material. It's not a horrible film, just not great, not even very good. The thing that Varmaji failed to realise is that taking five minutes to articulate a single line of dialogue and making your characters walk at a snail's pace cannot make up for the absence of an actual screenplay. Sarkar took the suspense from the film to which it's a tribute and turned it into ennui; consequently, it never realised its potential.
