Following recent word that Blizzard was contemplating changing how Rift Trials work in Diablo III comes word in this forum post that they have decided remove them from the action/RPG sequel, admitting they don't like them either. Word is, "we are committed to removing them," specifying that, "Jonny Ebert, he is hard at work. He's working with Roger, the gameplay engineer, to remove Trials." Here's where this currently stands:

Anyway, there was kind of like—it sounds like I'm defending Trials, at least maybe some people think that—that's not my intention. I want to say that—I'll keep my answer short. We've gutted Trials internally, we're working on it, there were some issues, it had a bunch of downstream effects, and we are still working on it. But we recognize that people are not happy with them. Asking for them to be removed isn't going to make it happen any faster. I wish it could! If I could make it happen faster I would say everyone should talk about it all the time, but, you know what, everyone talks about it all the time already, and unfortunately it just doesn't speed up how fast we can get them out.