...is that Darcy begins the letter by saying how much less important one of the offences is than the other, ("Two offences of a very different nature, and by no means of equal magnitude"), but then goes on to spend as much *time* on each offence. IMO this shows how much he cares about Elizabeth's feelings, even after she's rejected him. He seems to use many apologetic phrases and write more delicately about the Jane/Bingley topic than he does about Wickham. He even says a few flattering things about Elizabeth's (and Jane's) character.