It's clearly a yellow card. If it was intentional then it would have been a red. It was a fairly reckless hit that went wrong. Arguably worse than the one that McFadden got 3 weeks for as against an opponent who was also already dipping down he at least made the initial hit on the chest whereas Farrell misses his chest completely. If there were consistency in punishments Farrell would also be seeing a ban. I don't think that he will though not least because a ban wasn't really appropriate in McFadden's case IMO.
Clearly in touch with what's going on with Ireland as both Healy (bench) and Ross (starting) are included this weekend. I think that he's also wrong about where the game will be won and lost. It's more likely to be in the scrum. Poite is an idiosyncratic referee at the best of times but he typically rewards what he perceives to be the dominant scrum. A better scrum would have seen Ireland win both of their opening games. Healy is nothing like the player that he used to be and Ross usually needs a few games to get back to match fitness so while it's great for Ireland to see them involved again it'll be a minor miracle if they are up to speed.
It was reckless not intentional and merited a red card. You have to be an idiot not to know that there was a chance of kicking someone and hopefully it gives players inclined to be this reckless second thoughts about taking those kind of actions.
The commentators missed it but Owens (ref) clearly called 'still advantage' just before he chipped. He knew that it was a shot to nothing. A contrast to the boringly unambitious gits who attempt a drop goal when there's a penalty advantage in front of the posts.