What Are the Chances of a Mini-Deal in the US(P5+1)/Iran Talks?

The notion around the final day of talks between the P5+1 and Iran over the latter’s nuclear program is that there will be a 3-month extension that is most likely to peter out as hardliners in the US and Iran increase their domestic influence and compromise becomes harder to achieve. Now, I’m no nuclear expert, but given such prospects, wouldn’t it be in the interests of both the Obama and Rouhani administration to maintain momentum and make it harder for their domestic opponents to force them to pull back from an eventual final deal by baking in some mutual gains in a mini-deal? I would have certainly been working at that over, say, the last couple of days before the deadline, instead of trying to bridge all the differences in a last-ditch effort to reach a full-fledged deal.