If you think anyone described in that thread had a relic+1, then you can't read. Each one of them in the party was there because they couldn't get PUGs to take them so they could finish the relic quest.
Try Valk's calculator. At 350 strength and 250 determination for WAR, a DRG will deal 7.45% more damage per potency due to passive +32 strength advantage. Both have 10% vulnerability (SE for WAR, Disembowel for DRG) and 20% damage (Maim for WAR, HT for DRG) boosts. The only differences are abilities (Berserk vs. Blood for Blood) and weaponskill potencies. If you compare main damage combo, you're looking at 880 for WAR versus 900 for DRG after accounting for autoattack influence (100 potency per 3 seconds). That's a 2.3% difference there. DRG also has more powerful and frequent interrupt (if it can be used), better DoT (290/18s for Phlebotemize, 300/30s for Fracture), better secondary combo (760 potency on Chaos Thrust combo, 610 on Storm's Eye combo), et cetera, but the difference is small, especially after accounting for autoattacks. Base stat (namely, STR) boosts are identical on armors and weapon between the two jobs.
Furthermore, there is certainly no problem with WAR, who already rolls VIT-melded DPS accessories (Gryphonskin Ring/Neck + VIT + Battledance) or STR-melded tank accessories (Rose Gold Wristlets + STR) since STR is also mitigation. The only real question at all is where people put the bonus points, and given the abundance of seals, I don't think it much matters.
It does not directly affect enmity, but otherwise roughly correct. AA Potency is normalized to 100 per 3 seconds, so a weapon with an attack delay of 2.32 (Curtana) is 77.3 potency per attack. Based on P3 testing, Sword Oath adds a flat potency boost, raising it to 127.3 potency per autoattack. They might have changed it to a normalized boost (150 per 3 seconds instead of 100*delay/3 + 50 per attack).
Right. Both are a net enmity increase, but Shield Oath is a larger enmity increase (multiplier on total enmity; I've seen it theorized to be 50% before damage reduction or 20% after, but I haven't tested myself -- P3 modifier of double enmity is no longer true) than Sword Oath (damage-based enmity only, maybe 5-10% increase in total enmity depending on how much you're using RoH).