Huh? Dude, I grew up in Queens, and I took the train into Manhattan most of my life. The 7 train is one of the busiest lines in the system, and the Flushing stop alone see over 19 million riders a year. It's also one of most efficient lines in the system. People take the train all the time out to Citi Field, it's not a problem at all. The 7 line also stops at Grand Central and Time Square, two major hubs which branch out everywhere, even to Westchester, NJ and LI.
Yes, if a stadium were to get built out past Flushing, it would suck big time, but most of Queens west of Flushing is easily accessible by subway. If they can find a spot in this area, then it's a great choice.
Queens has an annual ridership of 245,692,630 and Brooklyn has 372,392,182. I am also from NYC and have taken every single train except the 7 train, and if youre in the city and ask most people they would say the same along with the G train. Brooklyn ridership went up 15 million compared to the 5 million queens went. If they build a stadium in Queens the only good spot will be VERY west before all the trains split up. Manhattan would be the best place or Near Yankee Stadium. Queens to most New Yorkers is a headache waiting to happen.