For me, BL is not just smut. Even if the story have a whole load of banging, if its devoid of story and character development, I will just skim the stories quickly without even admiring the art.
If the story doesn't have any sexy time, sometimes there's a disappointment because we've been reading or following this series for a good long years and the hope for some action because of the author teasing has become unbearable (lol), but even if it ended without any sexy time, as long as its story in itself is good, I'm fine with that (and actually many was like that too).
A solid story and character development is a must if you want to gather a 'real reader' that enjoyed the comic not because it has smut in it, but because the love for the story and the characters themself.
Smut or softcore sex is not a must, but story, plot, character development and pace is the key in my opinion.