I really liked the fact that Harry and Severus don't end up together at the end of this story. Let's face it, in canon's 'real life', they wouldn't either. They are too needy for exactly the one thing that the other cannot give.
Severus is a destroyed human being. Harry is also damaged, though a lot less. Frankly, had he had to live Severus's life, he too would be as destroyed. The only thing that saved him is 1) he didn't have to fight Voldemort for more than 7 years; and 2) Snape is always there to save him.
But being the rescuer is not a good role for Severus, though it is for Snape. He's played it far too long to be able to tell AD to go to hell when the old coot forces Snape to continue caring for Harry. (The OB may mean well, but his heavy-handed manipulation guarantees failure.)
Harry, on the other hand, is hung up on the kind of love he needs. He needs a sort of mature 'Weasley' love -- warm, cosy, touchy. Snape is not possible of that kind of love.
Severus needs to be loved too, but he's put his needs on the back burner for so long that he can't bring them forward. Harry doesn't know how to drag them towards himself.