No decent person in the world would snatch away the happiness from others, especially when it is Sadhna, who laid down her life without uttering any complaint. But people may argue that noone asked her to do. If Sdahna feels that the three are happy going back to RH, I think her silence means she does not want to stand in their happiness. or is she expected to say "please dont go there, Mummyji will insult me"....because, she is aware they have succeeded in just one step,...now oi they go back to RH, and Vasu asks them that she will not allow Sadhna in, what will the three do? I am pretty sure that they will never go onside without Sadhna and everything will be reduced to square one.
Ragini did say everything and she did it brilliantly, esp. the words that she said about her and Sadhna during the rift track. But the main question is alekh and ranveer left home and also when Vasu was faking sickness, then also they went leaving all their issues...how come their "khudaari" be given the name of "ego"...and compared in the same status as Vasu's arrogance.
in all, I can say its a mistake in the script, and the direction, they made everything possible to elevate Rgaini's character, except making her solve the core problem.