We can't predict that now...totally depends on general viewers.
Before Punar Vivah started there were so many naysayers , critics wrote the show off before it even started. But the show proved them all wrong and became a huge hit and AarYa became very popular.
Now with current couple leaving there is a huge chance to loose many viewers. But Cvs played it very smart. They took some excellent decision to maintain that viewership...
1) If the rumors are correct...that Angad-Sara will be the new leads then they already have a loyal fanbase who will watch the show for them.
2) The masterpiece is as rumors are saying that they will introduce the new leads while AarYa story is going on. Thus they will make all the viewers to watch the new couple along with AarYa. I must say this is nice trick to grab the eyeball of general viewers.
So it all depends on general audience...will they take it or throw it...only time will tell.
As for me I'm leaving after AarYa story gets over.