There's the Ultrajoe we all know and love. Missed you.
As to your discussion:
I don't play Space Marines, I play Space Wolves which, in my mind, is an entirely separate play style and canon. And, interestingly, the mainstay of my army is indeed female, or was once. I'm sure you would all be horrified by the mutilations my group and I have visited upon the canon during our universe-shaping battles, but as we are all individualists to the highest degree, we have difficulty accepting that the brainwashing of the Astartes is so complete that they will toe the Imperium's metaphorical line in the sand. Our heroes, our leaders, they all (with the exception of our Guard player) make their battlefield decisions based on what will result in the desired outcome, not on some invisible ideal of racial perfection.
I see the Space Wolves as separate from the rest of the chapters. They are much more individualistic, more willing to ignore direct orders. Each of them is a warrior and a creature of honor, actual honor. I have names, personalities, histories, tics and quirks for every single member of my army, simply to reflect this. They are monastic warrior-priests, but they are also simultaneously the most and least human of the Astartes.
That's why I have Femarines. That's why I play Space Wolves. That's why I think Femarines are not necessarily a great idea elsewhere in the Astartes.
The Space Wolves break canon in so many ways already that adding women to their ranks seems trivial. Elsewhere, however, the Astartes are representative of an extreme order, and are meant to represent both the best and worst of "manliness." To introduce a woman into those ranks would seem inane, as though suddenly the purpose of the Astartes (in my mind, to serve as a warning against clinging too firmly to any one ideal, in their case, manliness) had been lost.
However, this is within my group's Universe, within another, Female Astartes might be perfectly feasible, standing shoulder to shoulder with their brothers to defend the Imperium from the Xeno.
As to Black Heimdall: Yeah, I don't care. He's gonna knock the part out of the park, we all know it, people are picking at nits. There might be a reasonable argument due to the break within Marvel's canon, but, let's be honest here, they're rebooting the franchise for the movie, it's not like the movie is going to fit in with the comics anyway. If it helps, oh ye of rabidness, think of it as an alternate universe. Like DC. But less confusing.