I read the complete text of the Proposal and it appears to apply only to digital modes, which would exclude AM ans well as the ESSB crowd from being affected. The boys in Newington have only been lukewarm on AM and fairly noncommittal on ESSB, but it's hard to believe that they'd let a prohibition slide through without comment.
73 de Norm W1ITT
"IF" I were the ARRL ( and I'm certainly not ) I would lobby for a 6Khz limit..... You never know what future advancements or modes might require more than a 2.8Khz limit.
Don W4DNR