The busted thrusters was a stretch on my part. I figured out another way to explain why Kirk wouldn't have approached the Reliant from different angles.
You are Kirk. You want to capture Reliant. You decide the best way to disable it with minimum enemy casualties is to do the following,
1. Destroy/damage one of the Reliant's warp nacelles.
2. Destroy the Reliant's torpedo tube launcher box (the square box in the center of the weapons bar).
You want to do this because you want to capture Reliant. Your phaser lock is inoperative, so you want the largest surface area to target your phasers. As well, your torpedoes can't home well, so you want your torpedo launchers to be aligned with whatever you are going to shoot at.
You bring up a schematic of a Miranda.
Miranda
(From Bernd's site, hosted on my webspace)
If you approached from the front, you would have a good shot at the torpedo launcher. But so would the Reliant at you. This is obviously the worst choice.
If you approach the Miranda directly from the bottom, you would likely have the safest approach. But then, you would have a small surface area to target your phasers on the nacelles. And you couldn't even hit the torpedo launcher.
If you approach the Miranda directly from the top, you would have a good shot at the torpedo launcher. But you wouldn't have a bad shot against the nacelles since the surface area would be small.
If you approach the Miranda directly from the back, you would have a good shot against the torpedo launcher. But you wouldn't have a good shot against the nacelles since the surface area would be small.
If you approached the Miranda directly from one of the sides, you would have the best shot against the nacelles, and a pretty good shot against the torpedo launcher. But you want to hit the box, not blow off the whole weapons bar.
You choose phasers against the nacelles, and torpedoes against the Miranda's torpedo tube launcher. Therefore, you have to line up your torpedo launcher with Miranda's torpedo launcher, and your phasers with the largest surface area of the Miranda's nacelles. You have to choose the best approach angle so your torpedoes and phasers have the best shots against their respective targets. The back is the best way to align the torpedo launcher with the Miranda's torpedo launcher box. The side is the best way to align your phasers with the largest surface area of the nacelles. So you choose to approach from the back and slightly to the side, for a good shot with your torpedo launcher and your phasers.

(From Bernd's site, hosted on my own webspace)
Lo and behold, you are in position. You are not perfectly aligned, but that is okay. Your torpedo launcher is aligned with their torpedo launcher box. Your phasers are even able to hit the Miranda's torpedo tube launchers along with your torpedoes, and you blow off a warp nacelle with the phasers. Captain Kirk would have been proud of you.
Brian