When Chan Gailey replaced Barry Switzer as coach of the Cowboys after last season, the consensus was that a new coach - any new coach - in Dallas was good for two or three more wins following a 6-10 season.

Right now it looks as if the Cowboys might get more.Some reasons:

- The NFC East is awful - 0-7 against outside competition. The New York Giants are playing like Dan Reeves rather than Jim Fassel is the coach; the Washington Redskins are totally confused; the Arizona Cards have major holes on offense; and the Philadelphia Eagles are just bad.

- Impact players can change games, as Deion Sanders demonstrated Monday night. The Cowboys had four: Troy Aikman, Em-mitt Smith, Michael Irvin and Sanders. Aikman is hurt, Smith and Irvin are past their peaks, but Deion is, as he used to tell everyone before he got religion, a prime time player.

Some other three-week trends:

AFC-NFC Denver's Super Bowl victory after 13 straight AFC losses demonstrated what a lot of football people already knew - that the AFC is by far the better conference now. As such sages as George Young and the late Jim Finks used to say during the days of NFC dominance: "Things run in cycles."

This cycle is no contest.

There are probably a half-dozen potential conference champions in the AFC, even in this day when everyone is watered down by the salary cap. Denver, Kansas City, New England, Jacksonville and Miami have all played like contenders, and Pittsburgh will once it gets its offense straightened out. We'll know about Seattle after its next three games - at Pittsburgh and Kansas City and home to Denver.

Moreover, Tennessee, Baltimore, the New York Jets and maybe Cincinnati are respectable, giving the conference 11 decent teams.

The NFC may have 11 bad teams.

Only Green Bay, San Francisco and Minnesota have played like contenders, and there are questions about the defenses of both the Vikings and 49ers - Minnesota did, after all, almost blow a big lead in St. Louis. Dallas is probably OK, the Giants might be if Fassel can turn their heads around, and the Tampa Bay Bucs can make the playoffs if they learn that games have a first half as well as a second half.

But there are some awful teams in the NFC: Philadelphia, Arizona, Washington, Chicago (the Bears lose close games, but they lose), maybe Detroit, Carolina, New Orleans and St. Louis. OK, the Saints are 2-0 and so are the Falcons, who could challenge for a playoff spot. But the Saints are bad, and Atlanta is a mediocre team with an easy schedule.

QUARTERBACKS: They're either too young, too old or hurt. The Cowboys' Jason Garrett, who's been a third-stringer for five of his six years in the NFL, could probably start for a half-dozen teams.

DISAPPOINTMENT: The Lions figured to finish fourth in the NFC Central, but a respectable fourth that could get them to the playoffs again. Now they seem to have tossed in the season by inserting rookie Charlie Batch at quarterback.

Too bad, because Barry Sanders may be too old by the time Batch matures into a good QB. But it probably had to be done. Scott Mitchell is the classic coach-killer - he teases you with an occasional good game, or good three quarters, then kills you with stupid mistakes.

DISAPPOINTMENT II: (see above): Nobody expected the Giants to go to the Super Bowl this season, and they lost one of the keys to last season's NFC East title-winner when Jason Sehorn was lost for the season with a knee injury.

But they're still way down from last season, and fingers are starting to be pointed.

"Some people here aren't very hungry," says All-Pro defensive end Michael Strahan,

"I'm not going to point any fingers, but they know who they are. Some guys here really want to win, but a few people are dragging us down. "

The Giants signed a bunch of their young players to long-term contracts to ensure they don't become free agents. At the time, it was thought to be a good idea.

But if the only incentive for a player is financial . . .

Maybe that's why they've committed 26 penalties in the past two games.