I actually disagree with you. Suman is not the wall, or to say reason for anybody's actions.
Dadaji not accepting atharv is because of his ego. If he wanted to he would have accepted Sujata but he didn't and that is the reason Suman is in this predicament and not the other way around.
Ravish hiding his emotions is because he THInKS his mother will not be able to bear it. Its his thought process. From what I see Suman is not that fragile. Yes she will be hurt but she can take it. Ravish is just delaying the inevitable (and for that I don't blame him. Everyone does that at some point of time).
Vividha is pretending because she wants to be with Atharv. She was ready at one point to leave but when a convenient option was presented to her she took it. (And here contrary to many views I don't blame her either. I would have done the same). But suman comes a distant second in her decision and that's a fact.
So yes I don't see Suman as the reason for anyone's action, indeed she is the EXCUSE for everyone, including the cv's who are using her to continue the triangle.