i agree generally, although i don't do the AB comparison.
a lot also depends on need, obviously. that can take two forms: pushing you over the top, and unclogging depth at a position. the first one is easy: i once traded 3 good prospects for an older vet in the last year of his contract, which you might not have done. but he did fine for me all season, and hit a walk-off, come-from-behind HR with 2 outs in the 9th in game 7 of the world series for me. couldn't make it up.
the second one happened to me just this season. i traded a stud C/DH, a young RP, and a SP prospect for a big SP vet... but i had a comparable C/DH, and young pitching depth. might as well make a move since the guys i gave up, while high quality, were redundant in my system.