Kabir may be unable to join the Army again, but surely the Army could recommend him? I guess they aren't showing his Special Agent role, because that would mean he would have to stay away from his family.
Dhruv's character is annoying. He didn't have the guts to stand up to his father and now, his male ego has been bruised so he wants to go after Pooja. Instead of doing that by wit, he wants to do it by force - which makes his character even more unpleasant. His family is out on the streets, but he is too busy brooding. Even Jay-Sonali are being better pillars of support than him - at least they are trying to keep the spirits up, whilst Dhruv thinks only he has been wronged. Well, sucks to be you, but you asked for it by being clueless all this while.
As for Pooja-Kabir, I don't think the writers want us to think she is wrong. Her actions (to an extent) were justified. What they are trying to show is that because revenge was the main motive of her life, she has lost touch with her emotions, to the point where she even says that if Rani does not return, that's her problem.
She has spent most of her life thinking of ways to take PK Mittal down, and now that he is gone (for the time being), she does not know how to handle it. She is obviously not happy, the last scene was a clear indication of that, but she does not know how to be happy because she has never had anyone to make her feel that emotion. Rani is selfish and silly, and Pooja has had to spend most her life protecting her. When Rani is in the mood, she makes Pooja happy, but she does not truly care about her sister's feelings - else she would not be putting her through so much pain for a guy who doesn't give a s*** about her. Kabir, on the other hand, is the only sane Mittal (besides Jay and Sonali) and he has tried to warn Pooja that what she is doing now is not going to end well.
I suppose that is what the writers are trying to show - that revenge is futile. The only way Pooja would truly be happy is if she moves on and makes peace with the situation. The Sr. Mittals would have to pay for their sins, but she doesn't have to be the one to punish them, because it would never end.
When PK Mittal comes back, I am pretty sure Pooja and Kabir would join hands to take him down. That would be another interesting track. Here's hoping the ratings are in their favour and the show does well!