But that's just my opinion... Yesterday, I was playing the "School" map with a hero... and my favorite... each player for themselves. There's only a lumber mill, a mine, 2 gold mines, and 1 random mine. The neutral creatures are levels 1-3 in each of the "home" zones; there's no sign of Vampires there. So, yes, it depends on the map, but it's nice to find Vampires on the battlefield and activate auto-battle... it's a good strategy.
Regarding vampirism, I guess I'm just unlucky, but I've never encountered it outside of the campaign. As for ranged artillery, in my opinion, they're as useless as the Dungeon's. I prefer the 3rd-tier units to run and provide cover; that's good for the early game, and only then... Also, it's worth noting how stupid the AI is – when I'm already starting to conquer Rhanos, it still has a fort, but all the dwellings are built.
I agree about the fighters; they're the most useless 7th-level creatures, and they consume a lot of resources.