Why is a blitzkrieg impossible? From day one, we go to attack stacks of dragons (ignoring the phoenix quest), and along the way, we buy undead in the Necropolis. With Chaos, Machines, and the Log, it should work well. After defeating all the dragons, you can find Nicholas somewhere nearby.

You played by focusing on killing dragons, while I focused on collecting artifacts. :)
I'm not a professional in Heroes 5, and in my opinion, in the very early stages, there's simply nothing to even break through the garrison with vampires and other creatures around the Narcograd castle or whatever it's called. So, even if you manage to break through, what do you do next, and how do you proceed to Orange and beyond?
Now that I've obtained the phoenixes, I'm going to get reinforcements, but I can't seem to find Nicholas this time. During the first game, he pursued me through the dungeon and practically ambushed me. And Faidaen with the phoenixes now shines like a spotlight.