If indeed it is KSG who is playing the role of Bajaj then I must say it's a bold move by Ekta. I guess her assumption is that a lot of the audience are younger/haven't seen season 1 so they would not be bothered seeing the bad guy who played Sharad and was hated for what he did to Mukti now become a main/parallel lead and marry/live with Prerna.
No other cast members from the previous season are in this one, are they? (sorry if I missed it)