crop, crop, crop, crop....Basic rule in sport shooting, shoot tight, crop tighter! Eliminate distracting background to make players the highlight. E.g #4 is a great shot of the crowd but not the batter. For batters, the BOB (bat on ball shot), at least for me is usually a delete shot as you rarely get the players face (eg #5) however you are close in #4 but the focus seems more on the crowd. I prefer to capture batters as they come up out of their swing and follow the ball...you get great facial expressions this way and it is still pretty evident they hit the ball. Also, on bright sunny days, learn to overexpose a bit to reduce shadows on faces and under caps. #1 would be a decent pitcher shot (assuming he is in good focus) but crop tighter in post production.
PS: With your gear and location you should get some primo shots...for reference here is a link to a Mariners game I shot last year with similar seating, although on the 3B side, which may be a better location for shooting batters. All of these were with my 40D and 70-200 plus the 1.4TX...http://christianjstewart.zenfolio.com/p1021534075