So, I've played with raids a bit now and... they lose engagement really quickly. Once you have a few good units (i.e. Ferals), you can raid almost anywhere, and once you capture and convert one good realm unit, it's a snowball of victory. A single Inmate or Monstrosity is 10 cards on its own. Add nine ferals and you're drawing 20+ cards every turn, and amassing huge amounts of treasure.
Also, for all the things like adventurers, heroes, legendary finds, good and bad magic... you don't actually find them. Like, there are three ways to get good magic, one way to get an adventuring party, two to get bad magic.
All in all, it's got a lot more flavor, but a lot less depth than DELVE.