Pitting 24 Warriors (w/Spiked Shields = roughly 600 pts) vs. 60 Common Goblins (w/Spears, LA/Sh = 420 points)...
Assume 6 wide vs. 5 wide for test #1, assume Horde vs. Horde for test #2.
The Warriors swing first. Hit on 3's, wound on 3's, save on 6's. 12 hits, 8 wounds, ~7 kills. Goblins swing back. Hit on 5's, wound on 5's, save on 4's if the Goblins charge, 5's if the Warriors charge. 5 hits, ~2 wounds, ~1 past saves. Warriors maybe get an extra kill off the Spiked Shield.
The Goblins might grind this, but they're losing combat by about 4 or 5 until they manage to grind their enemies down.
Warriors get more attacks this time (32), so ~21 hits, 14 wounds, ~12 kills. Goblins get 32 attacks as well... ~11 hits, ~4 wounds, ~2 of them get saved (and Spiked Shield probably turns that into an extra kill). Goblins get out-killed about by about 10-11 wounds.
The Goblins might grind this, but they're losing combat even more steeply.
If you just magically abolish Steadfast (alone), those Gobbos kill between 1 and 3 Warriors and then get erased.
As is, the balance might not be perfect, but it sure ain't so heinously skewed in favour of the Gobbos that wielding that kind of nerf chainsaw is justified.
Edit: Forest Goblins would do better, but cost another 120 more points and at this point are barely any cheaper than the WDG unit.