If 25 dudes from the Warcraft Universe can go up against the biggest and baddest from the Legion and come out smelling like roses once a week, I'm not terribly concerned about DC's chances.
Compare these guys to the various crossover threats the DC universe has had to face, not the least of which includes Mongul's War World, Darkseid's Apokalips, the OMACs, The War of the Lanterns, and so on. Apokalips alone is an entire planet of low to prime-level metahumans which is designed primarily for war.
And that's not even considering the high-tier threats that threaten to wipe even those things out from the DC Universe. Comic books in general tend to go by the rule of cool, rather than any sort of sensible structure. While there aren't quite as many "cosmic" threats like in Marvel, where you have Galctus, Thanos, etc., there are several threats in the DC Universe that the heroes deal with on a regular basis. Guys that make portals to Earth to bring through massive armies rank as Tuesday there.
What matters is the relative strength of the armies, the champions who are the big bads that need to be brought down, and what distinct things they are capable of. It's utterly pointless to say "entire worlds are destroyed by him", because that has absolutely no worthwhile language. Entire worlds were destroyed by Doomsday, Lex Luthor, and any number of other villians. Hell, Black Adam ALONE wiped out an entire nation off of the face of DC Earth and fought dozens, if not hundreds of individual heroes to a standstill in a massive brawl in China, only to be stopped by a deus ex machina.
I'm not going to completely write off the forces of Azeroth as primitive, since they have a lot of magic and steampunk tech, but ultimately the scales are way off and we have no reasonably way to compare them to superheroes from DC, especially since in the lores for both, power levels vary so widely it's hard to get a good indication of who beats what. I mean hell, at one point Hal Jordan with two Green Lantern rings and a bad attitude
destroyed the universe to try and recreate it to his own liking.
And Garvin: JLI = Justice League International. It's a bit mid-90's, but they just brought it back. It's where Booster Gold, Blue Beetle, Captain Atom, Fire and Ice, Enlongated Man, and Captain Marvel hung out. On the note of magic though, Superfam's magic vulnerability is spotty at best. It can range from near-kryptonite (which has been getting nerfed for years) to "What, that hurt? Damn, must be magic/super/tech/mcguffin that can hurt me today."
Now if this were, say, Marvel Universe, and you restricted the Powers Cosmic from interfering, I dare say you'd have a more interesting fight on your hands, because overall you don't have scores of Green Lantern/Kryptonian/Amazonian/Batman Inc. waiting in the wings to utterly beat down anything that looks at Earth funny.
Though Hulk might be imba, tanks shouldn't DPS.