The tweets with "or" in them are more about which he personally likes more, not which is stronger:
“@ChaosSmurf: @ChrisMetzen Kerrigan or Queen of Blades?” Sarah.
“@_jcps: @ChrisMetzen Druid or paladin?” CLOSE. Love both. ...paladin.
“@charonites: @ChrisMetzen Jaina Proudmoore or Lor'themar Theron in 5.2?” Lor'themar came out feeling cooler, but Jaina did some Rockin'.
“@Bezlo: @ChrisMetzen Sauron or Darth Vader?” Vader ...but Sauron would kick his Sith ass...
“@Lactarded: @ChrisMetzen cake or pie?” Cake!
“@Jezi_Belle: @ChrisMetzen Saurfang or Hellscream (Sr)?” Love Saurfang, but GROM rules.............................................!
“@RorSChk: @ChrisMetzen Day of Tentacle or Monkey Island?” Love both / but Monkey Island for my nickel...
“@CEMOTucu: @ChrisMetzen Velen or Nobundo?” Nobundo!!! He has to work for it!!!
“@DwightCouch: @ChrisMetzen Captain James t or Captain Jean Luke” Kirk.
“@Valomir: @ChrisMetzen orc peon or alliance worker??” Peon. Work work
The ones specifically about which is stronger have "vs" in them:
“@saintstryfe: @ChrisMetzen Ok, now the big one: Thrall v. Queen of Blades” Queen of Blades... But I don't like it!!!
“@hitstreak: @ChrisMetzen Uther in his prime vs Arthas w/ Frostmourne?” Think Arthas still would have taken him. Frostmourne was no joke...
“@Frozencry: @ChrisMetzen How about The Lich King vs Queen of Blades?” Queen. I think the Swarm would make short work of the Scourge.
“@Corath: @ChrisMetzen Admiral Akbar vs Grand Moff Tarkin?” Ackbar!!!! Because Tarken can't repel firepower of that magnitude!!!!
“@jhanan: @ChrisMetzen Optimus vs. Thrall?” Damn... That's like the Gordeon Knot of geek questions...
So when someone asks "Aman'thul
or Sargeras?" and Metzen says Sargeras, it doesn't mean Sargeras is stronger. It means that Metzen likes Sargeras more than Aman'thul.