I suppose the point is, if you are going to mention Hawke in the epilogue, then why not mention how his/her romance panned out? Its obviously going to be of interest to those who played and cared about Hawke in DA2, and it would take hardly any time at all to just include a quick 'And they lived in great mayhem happily ever after' or whatever.
When it would take so little time and effort (literally, its just writing a single extra line of epilogue text for each love interest choice Hawke had!), it feels like something that just should have been there, given how much it would mean to the people who are interested in it. There just doesn't seem to be any reason *not^ to include it, when it wouldn't cost anything, and wouldn't require any extra time or resources to do.
Especially when they know that many DA2 fans were aggrieved not to have the last DLC for DA2 to finish Hawke's story, and that the appearance of said character in DAI was massively unsatisfying to many. To quote a line from Josephine in one of the War Table missions 'Why antagonize these people, when it would take so little to appease them?'
Any argument against this must take into account the minuscule amount of time and effort it would have taken to have included this. It really wasn't much to ask, and this is precisely the sort of thing that you *know* people who care about a character want to know about the most. Yet Bioware continually underestimate that, and their track record on romance continuity and content is always utterly woeful. Tresspasser was another prime example, with some romances getting some attention, others hardly any. When are Bioware going to wake up and realize that people care about this stuff, and whether you, they or anyone thinks they should or shouldn't, it doesn't change the fact that it is an important issue for them.
So stop messing this stuff up and making it seem like you couldn't care less about it! Because even if that's true, you shouldn't be letting it seem that way!