I recently found out the *A global benefits include free/ additional baggage. As long as I have sufficient level miles this year I will fly *A in my second trip to US (got LH gold via the status match offer and did not think it could ever be used to SAVE REAL MONEY).
As for the benefits on DL flights I completely agree (my last year experience in travelling within US).
NW was BETTER - allowed to select priority seats online at least. And this is in fact ST global benefit.
Bad luck SkyTeam