Would the average IRL human even survive Azeroth? higher gravity, world ending cataclysms every year or two, plagues that can only be cured by magic, etc etc…
Just on this basis alone the average Azerothian citizen is one Demon kill away from being Doom guy.
because they didnt stop the mana bomb.
because most time dragons are too high and mighty to use time to ALTER time but rather to “protect” the timeline.
who is to say that Earth invading Azeroth isn’t the dark end that was foreseen and we go and stop the guy because clearly he went mad?
no argument. time magic wont stop us unless its supposed to never happen, in which case we would be saved from the portal problem and this scenario never happens.
The mana bomb wasn’t an extinction event.
Also, I think it’s pretty telling that the argument for earth winning revolves around the Bronze dragons letting them.
If someone lets you win, is it really a victory? does it actually prove who is better?
Earth isn’t better its just that the Dragons wielding the time magic wont use it in that way.
granted, maybe all it takes is some little girl crying (or boy doesnt matter. /puppy dog eyes)
to say “a timeline where everything is destroyed and reduced to nothing isn’t a timeline worth protecting”
and if that don’t work “protecting such a timeline makes you no better than (insert expansion big bad here)”
then a mage extracts their dragon soul or what ever and uses them as a battery or tool or engine to reverse time after the raid defeats them for ilvl 420 pants
What happens if a feral Worgen or two gets loose on earth?
Except they’ve already proven that they will step in and help if they think there’s something worth protecting; the Defense of Mt. Hyjal timeline was untouched by corruptive forces. No signs of the Infinite flight, yet the Bronzes sent us there to make sure Azeroth won and the Burning Legion lost. I imagine there are more examples in lore as well, but i’m not a Loremaster and my memory sucks (though this one example already proves the point).
And honestly, the argument can be disregarded as goalpost moving anyways. If we’re bringing ‘but the dragons/alliance/horde will act with compassion and understanding, so they wouldn’t use X magic or Y tech,’ Then the same can be said for Earth. The only way ‘The Bronze dragons won’t interfere’ is if you put a narrative to the scenario, and there isn’t one. it was just “Who wins in Earth vs. Azeroth?”
And if you’re just asking based on who has the better means of destroying the other, Azeroth wins purely on having time-travel before even taking any other arguments into account.
Now that our armed forces have diversity, inclusion and pronouns, Azeroth wouldn’t stand a chance!
Sargeras would one-shot Earth.
Unfortunately, so do they. 
LOL, good point!
but, if the npcs of azeroth were so devastating they wouldnt need “players” to defeat these bosses. What would really happen is the npc heros would just stand there and wait for “players” to help them, but they’d never come as they’d be in global wartime conditions and stuff like global communications would be prioritised in defense. and the military would just pick off the stationary npcs 1 by 1 while they wait around for a “raid” to form
Not 5th gen stealth fighters or bombers. Hell, a modded SR71 could probably be useful with how fast these things go.
Azeroth has literal spaceships capable of nuking from orbit.
Ah, knew something was off.
No, Azeroth only has magical intergalactic spaceships that can fire from orbit…
Did I mention magic?
It wouldn’t even be close. The fighters would shoot down the dragons from miles away with missiles.
Semper Fi! 
If Azeroth can disarm nuclear weapons then Azeroth would win by a landslide. By Earth would win cause we got enough nuclear weapons to put even the fallout Francise to shame. Nuka cola anyone? Or how about rad ghouls? Loving that radiation yet?
Good luck trying to throw a fireball at something moving faster than the speed of sound, much less trying to hit it with your deathstar laser.
Yes, the Earth has nukes and the areas where they landed would be decimated like Hiroshima and Theramore.
But Azeroth has gnomes that radiated their own city and with a quick wash in whatever water they developed any remaining radiation would be gone.
Also have to think about the portals being monitored at this point. Both sides know each can just throw or fly something through them so if a nuke was to appear whoever/whatever stationed at the portal on Azeroth’s side would get rid of it. Along with themselves and probably the portal.