While i agree that trusting no one doesnt really solve the problem, I dont believe it is "just as bad" as trusting everyone. Trusting everyone stops other rules from firing and adds atleast -2.something to every message. This seems far worse than trusting no one and breaking whitelist_from_rcvd
While I'll concede it may not be "just as bad" it's still much worse than you think.
LOTS of rules in SA depend on trust. Not just whitelist_from_rcvd and ALL_TRUSTED.
All of these rules are broken by a broken trust path, some in ways that cause FPs, others just missing out on score:
HELO_DYNAMIC_* FAKE_HELO_MAIL_COM_DOM RCVD_IN_BSP_* MSGID_FROM_MTA_ID FORGED_RCVD_* AWL
trust plays into "notfirsthop" as well, so all these DNSBLs get broken:
RCVD_IN_NJABL_DUL
RCVD_IN_SORBS_DUL
RCVD_IN_XBL
RCVD_IN_DSBL
RCVD_IN_MAPS_DUL
