Hi Pratibha ,
First off Welcome to the Forum!
Second, much like the comments already expressed here, I am also one who liked DH and although the epiloguge was a bit irritating, because much like you I found it "too perfect" , I however don't necessarily disagree with the sentiments conveyed in it.
I like the Ron Hermoine pairing. I've seen it develop from book one, and I can't say for certain that the relationship would have turned into an abusive one. (This is meant in no way to trivialise your own personal experinces) Abusive on whose part? Ron against Hermoine? or Hermoine against Ron? Because as far as I could tell, Ron may be the "tough talker" with his insults and comebacks, but I think that Hermoine is a strong enough girl\woman to know that when someone is not treating her as she should, she whould demand that respect. She did it with Malfoy in POA. Further who is not to say that Hermoine wouldn't have been the one to turn abusive. She set some canary birds on Ron once in HBP in a malicious attempt to hurt him. I'm just saying that looking at a few pages of the epi. cannot give any definitive conclusion that an abusive relationship existed.
As with the "reality" that High School sweethearts ending up together. - I think she can't look at it from that perspective. Normal High School students only have their grades, and parents to worry about and by the time they are 18 barely know themselves or their purpose in life. They are now strating to figure these things out. Compared with your HP characters, who by the time they are 18, they have faced a lifetime ofproblems that have forced them to mature well beyond their years, so , to me, it is entirely plausible that Ginny and Harry and Ron and Hermoine should know that they are meant to be together.
Finally as with the "all is well" ending, I don't believe that it meant that everything is sunshine and daisies and all is perfect in the world. I can decribe my life now by saying all is well, even though I like everyone else has a myraid of problems to deal with. But I do have my health and my family, I have food to eat and a place to sleep. Much like the HP characters who have family and friends to love, a relatively safe life etc. There exists the possibility of evil in the future, but why dwell on it on the day that you see your children off to school? So at that point in time All was well for Harry and gang.
Anyways these are just my take on the issues you presented, but I have a question - do you dislike the ENTIRE of DH or just teh final scene. Would you have preferred it to have ended after Harry went to bed that night. - I know I would have, but I don't detest the epi. just mildly irritated by it. :)
I meant nothing in here as offensive so please don't take it as such and Thank you - its been a long time since I wrote such a long discussion post on the HP forum so thanks for starting the topic - even though you meant it as a place to vent ;P)