The key elements to the hooker's game are line-outs and scrummaging, and because of the way the game has gone, he has to be like a loose forward in open play.
He's likely to be the last up at every second breakdown, so he'll need to be around for support and ball carrying.
Having a really big, heavy guy who can't get across the pitch is a waste of a position in modern rugby.
Like all rugby players these days, the hooker has to be able to handle a ball, but scrummaging technique is going to become even more important with the change of rules.
Flannery's throwing is the best I've seen, and he's a hard, aggressive, bolshy guy
Before, you could get away with a little bit of a charge, but now the charge is more controlled from a short range, so guys with good technique will do a lot of damage - good damage.
When packed down, a good hooker will try to get a lot of pressure through his right shoulder, and will do an awful lot of standing on his left leg as he goes for a sweeping strike down one of the channels.
Striking for your own ball is important and though you rarely strike for the opposition ball, it depends on the scrum.
It's considered the height of arrogance to strike against the head but I always tried to have a go at one or two.
One of the best hookers around at the moment is Ireland's Jerry Flannery.
He was the best number two in the 2006 Six Nations in his first international season and he was fantastic.
His throwing is the best I've seen and he's a hard, aggressive, bolshy guy.
He probably just needs to work on his speed.
He sent me a great message after one game last year, when he was caught while trying to score in the corner at Lansdowne Road. He said the quicksand got him.