They don't bunt well enough and don't hit-and-run enough, which some people believe will be the reason they don't win the World Series for a second straight year.
The first thing you have to do after hearing such complaints is wonder whether these people woke up from a 70-year coma over the weekend and wonder if there really isn't something better for such people to do upon their miraculous recovery than worry about the Yankees. Bunting, be it for a hit or to move a runner over, and using a lot of manuevering on the basepaths is a great way to overcome a lack of punch in a lineup.
Carig does a great job of debunking this argument, but, long story short, the Yankees have no such weakness.
The Yankees have the most runs and best on-base percentage in baseball and rank third in slugging percentage. They won the World Series last year on the back of an offense that was even less flexible than the one they currently employ and you'd be hard-pressed to find any member of the regular lineup that you'd rather see giving up an at-bat than trying to do something positive while at the plate. And that includes Derek Jeter who seems incapable of doing anything other than hitting into double plays with runners on base this season.
If the Yankees do fail to win the World Series this year because they don't bunt well enough, they will be the first team in the history of this great game to lose a chance at a ring because of that shortcoming. This is the sort of thing you'd expect to hear about a 1998-style juggernaut team that has forced fans to really dig deep to come up with something to worry about after months of domination.
These Yankees shouldn't make anyone work too hard. Just look at the last four performances from the rotation. Ivan Nova and Javier Vazquez couldn't get out of the fifth inning in victories while Phil Hughes and A.J. Burnett continued their inconsistent seasons in losses on Sunday and Monday. Worrying about bunts against that backdrop is like worrying that your army won't have enough toilet paper to get through the war when you aren't sending them into battle without ammunition.
It's about the pitching. It has always been about the pitching and it will continue to be about the pitching all the way through October.