I can't say I agree with you this time. Yeah, it's a spec script that's being rewritten, but I wouldn't put it past them to still push it out with the white male lead.
As Zoe put it in that thread, it's concerning that it was written that way at all, and as another poster (sphagnum? Or something like that) joked, after Disney cryptically responded that the love interest would be Asian, "Well duh, Mulan will be the love interest for the white guy." And this doesn't even touch upon the question of why Mulan needs a love interest at all.
I feel like the white savior trope--even if it isn't new, per se--is the new hot thing for movies right now, after all the criticism over whitewashing may have finally hit Hollywood's tone deaf ears. And even though it's Disney, and they generally have a better track record in terms of ethnic casting, I still don't find it far-fetched that that progressive attitude won't extend to Asians. They are already glossing over Asian-Americans, and even in Agents of SHIELD Chloe Bennet is half white, and even she felt she had to use a whiter-sounding last name to get work at all.
And then you have Birth of the Dragon. You would think that, of all people, Bruce the motherfucking Lee would have enough fame to warrant a biopic where he is the main character of his own movie, set in the exotic lands of San Francisco, instead of some made-up white guy. But no.