The way congress has functioned in last 60 years goes on to say a lot about how will it behave if Rahul becomes party president. As an outsider it always seemed that the party has taken ideas-decisions flowing from top leadership and/or their coterie. Unlike BJP(not Jansangh) or CPM it has been more or less a single focal point party (till 90s). We see that unipolar distribution returning to shape even now under Sonia. This either shows rest of the party politicians doesn't have an universal acceptance or Nehru-Indira-Rajeev lineage is exceptional in leadership. The second case however is less likely to be true. That was my first point. Secondly, Rahul will quieten the voice of opposition over the foreigner issue. Thirdly, we can see some young sophisticated(psuede) blood infused to the party lately; so it will gel quite well within it. The grassroot workers did not have much problems with the family. So according to me if Rahul takes over, he's morelikely to succeed atleast initially.
