What you remember from Once Upon A Time in Mumbaai is Ajay Devgn's brooding eyes, Emraan Hashmi's earnestness and dialogue writing that refuses to rest and annoys with its filmy-ness. What you figure from Once Upon Ay Time in Mumbai Dobaara's trailer is that you have no relief from the dialogue and you have Akshay Kumar and Imran Khan playing it out. Not to mention that the title is a mouthful.
Akshay Kumar replacing Ajay Devgn in a sequel only implies a good bye to subtle expressions and a welcome to loudness - thrice over. It doesn't help that the lines sound 'filmi-er' by themselves, if it were possible.
While Once Upon A Time in Mumbaai wasn't the greatest narrative, it had an engaging story. This second episode, however, seems to be more of a love triangle rather than a story of the workings of Mumbai's underbelly. If the underworld is going to mix its romance with guns, I hope they have been able to digest it well.
The music too seems to have received only lukewarm response too. The only hope is that you walk in with minimum expectations, so everything good you get then will be a bonus.