I'd say QB in football or goaltender in hockey/soccer. If you want, you can also include entire units of players (say, OL in football).
In terms of actual effect, QB in pro football (college football is very different). In terms of potential effect, a hockey goalie certainly can take control of a game or a playoff series more than any other individual player can, but that isn't what usually happens. Considering how many fewer scoring chances there are in soccer than in hockey, I wouldn't put soccer goalie close to these two at all.
NFL: QB NCAAF: QB or RB NBA: not position-based, but talent based. All talent being equal, a franchise PF/C NCAAB: PG MLB: Catcher, imho. Maybe a starting ace (but that didn't help Seattle) NHL: Goalie
Besides quarterback, a pitcher is the most important player in sports. I know they can't control the amount of runs their team scores, but they can control the other team to a certain extent.
There is no sweeper position in curling, the athletes rotate every round. Learn your curling before you post about curling.
In football, an average QB can be made to look great by a great OL. Likewise, an average OL can be made to look great by a great QB. In hockey, an average goalie can be made to look great by a great defense. Likewise, an average defense can be made to look great by a great goalie. In baseball, there is that link with pitcher and catcher, but I don't think the influence that they have on one another is so great. I don't think a great catcher is going to make an average pitcher suddenly look great. and I don't think a great pitcher is going to make the catcher look great. At the same time, a pitcher, goalie, or QB all can completely take control of a game. Although the QB is the only one who can actually score points (well a pitcher can bat in the NL and a goalie can score an empty net goal on occasion). It's a tough debate really.
The first guy in the 4 man bobsled. The other guys keep moving their heads to see where they are going, and the front guy keeps moving his darn head in the way! Total control freak
As a fan of a team that lost solely because they lacked a decent one, I have to go with hockey goalie. A starting pitcher is important to an individual game, but he only throws 1/5 games. Football is such a team sport with so many ways to win that you don't even really need a "good" QB, you just need one that won't actively lose the game. But a hockey team with a shitty goalie is going nowhere, no matter how deep they are everywhere else.
I can think of a few football teams that have one with bad QB's and nto any NHL champs that I look back and say "well the golaie sucked, but the rest of the team was awsome". As recently as big bens first SB, the Steelers won with very average to poor QB play. Football teams can win without great QB play. A hockey team with mediocre golatending is not going anywhere. No position in sports allows for as little room for error.
