Pretty good video. But disregard almost all the tackles in the first two minutes as they aren't rugby style tackles. Once Carroll starts actually breaking down the technique, then you see rugby style tackles.
Having become passionate about rugby over the past ten years, there are a couple of things about rugby style tackles that help to understand the approach.
1. It is illegal in rugby to try to tackle somebody without wrapping your arms. Can even get you a yellow card (ten minutes out and team down a man) if you do that, so you almost never see it.
2. Second key element of the rugby tackle is to put your head behind the path of the runner instead of ahead, or through the runner. The reason here is that if you are a rugby player, you may do this once or twice (head in front), and then your career may be over. You just can't take that hit padless without risking serious injury.
3. Three yards typically means nothing in rugby. The rugby tackles you see in the film are almost all open field, the hardest kind to make. In rugby, giving up yards midfield to get the good tackle doesn't matter too much. So the idea of a grab and roll tackle is just fine.
4. You almost always have support in rugby. In rugby, the line of scrimmage moves with the ball as the play proceeds. The defense will always (try to) have a line of defense strung out, so you almost always have a guy a couple yards away to come in either on or (preferably) right after to try to take the ball away after the tackle.
5. Putting a good lick on a guy in the tackle isn't really part of the game. If you are after a guy (and that does happen in rugby) you're more likely to go for the elbow in the head, the face rake, or the eye gouge. You're really trying to be more like fly paper than a freight train in rugby tackling.