"All my life, I'd thought that, "I can't stay with you," meant, "I have to leave." But instead, it means, "My ship can't keep up with your ship anymore," and that makes a lot more sense. It also makes Luke's line, "You can't do any more good back there," make more sense."

He still could have fallen back, and taken out a Tie from behind. It's not like they followed him out of the trench. Hell, Vader probably thought it was done on purpose to draw fighters away (which, I might add, worked later in ROTJ.)

"As for Wedge replacing Han in the trench attack, I'm all for it. It's always bothered me how Solo, unprovoked, fires on Vader. It makes him seem like a murdering pirate instead of the patient, tolerant, friendly hero that he is."

LOL...shooting from behind, I might add. Hell, he even enjoyed shooting down the Tie. Such a brigand!