Omens of Destruction is a meaty DLC that adds one of my all time favorite Total War: Warhammer 3 mechanics—and no, it isn't goblins riding other goblins
I've never particularly played much of the ogres in Total War: Warhammer 3. Don't get me wrong, I appreciate their whole vibe as a tide of hungry humanoid giants eating their way across the old world, and I love their monsters, which all look like prehistoric beasts taken straight from the cover of a heavy metal album. I also have a soft spot for Gnoblars; the Ogre Kingdom's stupider subspecies of goblin who love nothing more than filching through scrap to find a fun object to wear on their head.
No, the thing that put me off ogres was the personality of their legendary lords. I found it really hard to enjoy either Greasus Goldtooth or Skrag the Slaughterer; the first just sits in a chair the entire time while Skrag is honestly pure nightmare fuel. It's one of the reasons I was so excited to hear about Golgfag Maneater arriving in Omens of Destruction—finally an ogre I can get behind, though that's probably the last place you want to be in relation to an ogre.
Golgfag is by far the most interesting of his race, venturing far from the Mountains of Mourn in search of plunder and good eats, and in fact lends his name to all ogre mercenaries, collectively known as 'Maneaters'. This got me pretty jazzed, because I figured a mercenary faction arriving in Total War: Warhammer 3 meant that CA would bring back my all-time favorite mechanic from Three Kingdoms, and it didn't disappoint.
Mercenary contracts were a big part of the bandit playstyle in Three Kingdoms, letting you aid other factions in their wars, earning rep in exchange for rewards, and gifting captured settlements to your client. It was a properly cool mechanic that let you play sides while also accruing a mountain of gold, and for me, its return is by far the highlight in Omens of Destruction.
Golgfag and his Maneater faction can pick from a list of contracts and teleport to any of the client faction's settlements, allowing you more of a globetrotting playstyle similar to a legendary lord like Oxyotl. Alongside the new Ogre Kingdom's rework, you can pack up a camp and lay it down in any new region you visit, giving you a recruitment centre even if you suddenly find yourself a million miles away from your faction base.
It's pretty fun and unique as a playstyle on the whole. A part of me does feel like Golgfag needs some kind of additional mechanic beyond completing contracts, earning endless gold and meat, and shipping it back to his camps. It doesn't feel like there's as much of a clear campaign progression with you hopping all over and being able to make peace with a faction as soon as your contract ends. That said, Golgfag does get some special regiments of renown which help you feel more like a legendary merc leader.
Ogres also get a brand new legendary hero in Bragg the Gutsman, as well as more mountainous beasties like the Thundertusk, Yhetees, and Blood Vultures, which fill out and diversify their roster a bit. Most important of all; Gnoblars riding other Gnoblars, which is the most Gnoblar thing I've ever seen. Pigback Riders are what happens when you try to explain the concept of cavalry to a goblin, and their regiment of renown variant, The Piggyback Knights, might just have the all-time best unit description.
While Gorbag Ironclaw and the greenskins win in terms of units—hard to top a Colossal Squig—he's still kind of the most generic orc warboss possible. Similarly, Skulltaker gets some amazing unit additions, including heroes like Scyla Anfingrimm and Skarr Bloodwrath, but as a Khorne lord he's still primarily focused around that classic Chaos playstyle of razing settlements and general despoilment.
If you don't feel like picking up all three and want a wholly unique campaign more than just shiny new units, I absolutely recommend grabbing Golgfag and having a fun time making meat and murder as you merc your way around the world.