Still had to do considerably more work for every other companion.
Way more for Lae' Zel, Shadowheart, all of them really.
And where's the problem? I think it's more interesting if there's variety to it, the other romances seem to follow the more traditional way of first getting closer to each other and then intimate, with Minthara, you barely know her and it feels more like casual rather than romantic sex, but after the scene it is implied that there could be more to it and that Minthara isn't one to open up easily. I think it's a great starting point, if you can live with the atrocities you had to do to get there.