I want to restructure my workout a little to focus more on a) losing weight, b) quickness and agility, c) explosive movement, and d) endurance. It's kind of a tall order, but I'm a tennis player and I think that all of these goals are necessary. I'm a 17 year old female, about 5'9'' and 155 lbs. I'd like to incorporate more plyometrics, if possible. And now, the new routine...

Cardio
20 min intervals (2 min hard, 2 min easy)
14 min Tabata (5 min warmup, 4 min Tabata intervals, 5 min cooldown)
Jump rope (200x, as fast as possible)

Tues/Sat
Dumbbell bench press
Abs - bicycles, leg raises, exercise ball crunch, plank

Thurs/Sun
Lat pulldown
Bentover row
Star jumps

So basically, I'll do cardio every workout day, and then follow the cardio with the exercises above. Normally, I'll do either the intervals or Tabata, but this week is spring break so I have more time, and I can do both. This week, I'll also be finishing the workout with steady state cardio for as long as I feel like (I'll read something).

For the weighted exercises, I'm doing 5 sets of 5 reps; each ab exercises will be 5x20, and star jumps will be 5x15 (if I can do that much).

Any ideas on how to change this to hit my goals?

You got the cardio down right but you need a solid Weight Lifting Routine. Try a upperbody/lowerbody split with all the major compounds like the Squat, Deadlift, Bench Press, Military Press; all that good stuff.

Since your doing a sport, I know Tennis is really good for agility/quickness. You could even do shuttle across the tennis court to make it kind of sport specific also.

The only problem with an upper/lower split is that I think working hard (for example) on my bench will affect how hard I can do the pulldowns and stuff, so the above workout is my attempt at a push/pull split, although the only push/pull parts are bench, lat pulldown, and row.

I'm trying to replace the squat with star jumps and lunges, since I don't think that the squat has a lot of application in tennis. Deadlifts make me really nervous because they make my back feel really weird - is there another exercise I can replace it with? Bench, I've got, and military press, I'll add that with dumbbells.