Merril deserve elven(especially mage and dalish) lover/husband who will aprove and support her researches for the sake of her kind, not some shem who live with mommy and uncle for more than 10 years and do not inprove his rerationship or get married, have a child and do many sh*t
Hawke does not deserve Merril
Except the rivalmance (and even rival friendship) has Hawke conflict with Merrill because they're trying to make her see that her obsession with the Eluvian is damaging her life. While it's easy to do the friendship path and you want to because she's sweet, you're basically coddling her and agreeing that her obsession is more important than everything else in her life and she is right to put her own life in danger to try to restore an old mirror that even her Keeper thought she have stayed buried with the past.
It's not about the Blood Magic, that's only part of the problem and while Hawke can berate her for it, the real problem is the Eluvian. She's neglecting her friendships with people (if you don't romance her, Varric has to bring food to her because she becomes a complete shut-in and forgets to eat) and has become ostracised from her own people because she's too stubborn to let it go.
While restoring the Eluvian would be a great boon to her people and I can both understand and see why she wants to do it for the sake of understanding lost Elven knowledge, the truth is that a normal person would not see a broken mirror that was corrupted by the Darkspawn Taint that requires seeking out a Demon and learning Blood Magic to cleanse it, as being a worthwhile endeavour.
As for living with his/her parents, dialogue with Aveline in Act 1 implies that Hawke wasn't still living at home before their family fled Lothering (although it's suggested they still lived near), but returned either to fight in the King's army or make sure the family got out of Lothering safely. In Act 1, the entire family is forced to live with Gamlen in his shack in the slums, which is far better than some refugees who were forced to live on the streets or in Darktown. By Act 2, Hawke has bought back the estate for both themselves and a gift for their mother, so she can live the rest of her life (unfortunately, far shorter than anyone could have dreamed) in comfort in her childhood home.
And if I can speculate for a moment, part of the reason that Hawke might not mind everyone living in their estate and is willing to also take in Bodahn, Sandal, Orana and their love interest is because otherwise it'd just be them and their mother living in a great big empty house. We know that most of the nobles in Hightown have tons of servants, guards etc and most of the other noble's estates we enter into are huge, so the small scale of the Hawke Estate is incongruous given that we also know the Amells were once powerful enough to nearly take the Viscouncy for themselves. That and the fact it has wine cellars that reach all the way down to Darktown suggest that we only ever see a fraction of the Esate in the game and in reality, the place is absolutely massive.
I'd also disagree that Hawke's relationship with Merrill should be measured on whether or not they get married or have children. Most couples in our world neither get married or have children, either by choice or otherwise (and in some countries, to be married to someone of the same sex is nigh impossible), but that doesn't make their relationships any less important.
I also have to point out that Merrill is Dalish and believes in the Creators and Hawke (nominally) follows the Andrastian religion and believes in the Maker. Asking her to get married in the Chantry is probably out of the question, since I doubt Merrill would want to get married in the church of the Shemlen God, nor do I doubt anyone would even agree to conduct the ceremony anyway, since the Dalish are often considered "heathens" by the more pious of the clergy?
Asking for a Dalish ceremony is also out, given that we know that many Dalish frown on their people fraternising with Shemlen (Arianna had to leave her clan because of it) and even though Marethari's clan are somewhat more tolerant, I suspect that most of her clan would frown on it simply because it's something that Merrill wanted to do.
You're also ignoring the brave step that Hawke and Merrill take as a prominent couple in Kirkwall. It's common knowledge that many people in Thedas have their odd dalliances and children with their Elven mistresses or lovers, but it's always on the sly and mentioning it in public is considered taboo, especially among the nobility. Instead, Hawke is a noble who not only openly lives with and acknowledges an Elf as their lover (and a Dalish Elf at that), which is practically unheard of.
I think Hawke deserves Merrill as much as she deserves him/her.