#1: Preparation; firstly you are just way too late in your prep, so you are moving to the ball with your racquet still in front of your body. The ball has bounced and your racquet isn't even behind your hand. Roddick takes his back in front of his hand like you do but has much earlier prep and would have his racquet into acceleration when the ball has just bounced. Check out Agassi for a good early prep. Also notice his better L arm extension.
#2: Rotation to Contact; The ball is now in a similar spot in both pics, notice how you are side on still with no rotation of hips or shoulders into the ball. Agassi has now rotated and created racquet lag which will enable more racquet speed through contact
#3: Contact; you are still side on, your contact point is at or behind your R leg. Your weight is on the correct leg but really not pushing into the stroke. check out your elbow behind your body, a really weak position to be in, Agassi's is pushing out in front in the pretty common "double bend" position. His racquet is now leading his stroke.
#4: Extension; Your elbow has not moved and your forearm/wrist is creating all racquet movement forwards. Agassi is now driving upward and forward from the shoulder and is most easily recognised by the distance his elbow is from his waist.
#5. Follow Thru; You are achieving a front on finish not by driving the R side of your body forward but by pulling your L leg under. Racquet is on a similar plane and has not been driven upwards or outwards so has comfortably finished in front of the body. Agassi has really pushed his elbow upwards and forwards and his racquet is slowing down beyond his shoulder and requires this length to slow down with the least effort.
#6. Recovery; Due to your short jab stroke you have recovered easily but how effective was your stroke? Agassi is moving back to centre but note his racquet is still wrapped around his body.
Summation : Your FH is way too late in preparation, this does not allow you to therefore transfer your weight into the stroke with an early contact point. This lack of an early contact point will restrict your ability to generate power and spin.