Well, I agree with him. He can't write villains well, as demonstrated by the fact that we're all pining over Solas, even though they've pretty much set him up to be the next one. Is it the semantics that bother you? Is "antagonist" a better word?
Sure, they may pull something out of their asses to change the entire story for we Solasmancers, but I sincerely doubt it. Yes, I'm walking the hardline here, because I'm just so very very disappointed. I don't think I'll ever be able to finish a playthrough romancing Solas now, knowing that it might as well have been just a big inside joke for them. (And yes, I know that Mr. Weekes invested a lot of his emotions into it. That doesn't change the fact that the Solas romance was added just to make Solas more sympathetic.)
First of all I'm sorry that you feel that way. It's always a pity if someone is so thrown aback that they can't go through with a certain story line / character quest due to being disappointed. It sucks.
But, and it's a gentle but, I think when Weekes said they added the romance to make it "sadder" I don't think they did it to make him more sympathetic. Personally, I think many thought he was an idiot or ass or both for breaking it off the way he did until we got that snippet of "he nearly told her" from Weekes. That they added the romance tells me one thing: that they wanted to make Solas' character more complex. Let me try to explain this one and its implications:
- all side quests and stories involving Solas show him caring about other people and things than the bigger picture. Take his caring for Cole. His personal quest where he cares about saving his spirit friend. And of course the romance, where he cares about the Inquisitor.
- the romance shows him reflecting on his believes even more so than he does with a friendship-quizzy.
- the romance brings him to a point where he nearly gives up on the big picture, his big motivation. Nearly. This is important, because in realizing he can't go through with telling the truth and comitting we learn an important detail about Solas' character: his guilt, longing to make things "right", desire to "better the world" are stronger - or valued as more important by him - than love and his own personal happiness.
- this is important as it sets the stage for the sequel: a man so devoted to make things right that he sacrifices everything (AGAIN!). Because basically, his friends at the inquisition, especially the Inquisitor and Cole, are everything he has besides spirits and long lost memories. He breaks it off with the Inquisitor by leaving and with Cole by shutting off his mind.
Could that have been done without the romance? Sure, and to some degree you already get the picture even if you play as a male dwarf to whom Solas is just a friend. But in adding the romance the writers underlined his motivations and heightened what drives him, all while giving the players a romance option that is so very different from the rest of the romances available in the game.
The writers often state that they really care about their characters, and making Solas look more sympathetic is a task they could achieve far more easily than producing a whole romance plot just for that (not to mention all the money the extra development costs). They're too good writers than using such simple plot devices (with questionable outcomes).