He easily would have broken that barrier if WD didn't insist on using him like shutdown forward for some stupid reason in the first half of the season (when we had Sutter on the team too for christ's sakes!).
I've always felt like his defensively game in his first two years has been a little overrated (not to any fault of his own though) and has been propped up by his reputation. Horvat has been impressive these two years mostly because of his offensive jam, intensity, and smarts. He's willing to do the little things, but he hasn't come close to figuring it out yet.
I disagree with your first paragragh... Horvat deserves a lot of criticism for his play the first couple months of the season.
Only so much you can blame the coach or the opposition. He played like he had no confidence. Then he and Baertschi sparked up.
But nothing tangible appeared change in the coach's usage of him that I'm aware of.
He began to dry up offensively after his spurt when he began to try to do it all himself... maybe a little too much confidence in himself (or not enough in his teammates)...
When figures out the balance - the consistency will come. When he becomes consistent, he'll be a stud.
Now we wait for him to figure it out... only thing it will take is games... i.e. experience.