For what it's worth, I'll throw my two cents into this topic -- some people, after all, seem to take the "insult to the creators" stand when opposing a mod like this, and ever since I tweeted that I welcomed the mod's return, I've received a fair bit of "I can't believe you would do that!" comments as well.
The way I see it, it's a bit like the concept of free speech.
I may not support what you have to say, I may even be vehemently opposed to it, but I support your right to say it.
So either I support the right of fans to take my characters and create their own versions of them -- whether it be in a mod, in a piece of fanfiction, or in fan art -- or I don't. Period. Anything else would be hypocritical.
And I do support their right to do so. What they create doesn't change the characters I made -- they will continue to exist as they are now, and aren't impacted one iota. Cassandra will continue to be straight, Dorian will continue to be gay, etc. etc.
Now, like free speech, having the right to make whatever kind of mod you like doesn't mean you are free from consequences. You are going to receive negative feedback from people who don't think anyone should want the kind of mod you're making -- but I don't think that negative feedback elevating to the level of harassment comes anywhere near the level of "appropriate consequence". I was angered by the harassment of the mod maker in the same manner I'd be angered by a book burning or a witch hunt against "evil pornography" or anything similar...and, yes, it is the same thing. Everyone who does that feels correct and self-righteous when they do it. That's the nature of a witch hunt.
So I support the right of any modder to go in and alter Cassandra or Dorian or whoever else to their heart's content, if that's what they want. Obviously I'd prefer they enjoyed the characters as we created them, but that doesn't matter. Change their appearance, change their sexuality, change their story, their ethnicity, whatever kind of headcanon you'd prefer.
That indicates neither my support nor endorsement of the content, but regardless of that I am not offended by its existence. Cassandra certainly is not, even if she could be. Hell, if it was fanfiction, she'd probably read it.