The Barkskin Amulet is to stop the mass Javelin/Arrow that will often take out Ethereal and Luck creatures by sheer numbers. It's an important survivability tool early on and since Vampires already come with Regeneration you don't have to save them for Rings of Regeneration and can spend them semi-frivilously, depending on the Setting of Indeps.

Your normal army is as fast as any other out there in expansion. So don't leave that out of your tests. If all you had to deal with were the Vampires, it would be simple. But you do not always want to send them solo in against an opponent. And massive softening of human players with Rangers, then having the VC fly in and start letting his fear affect everything, most will break.

The key to indeps and expansion early on is learning morale and how to abuse it.

As for the mages, Nether Darts are just fine in my book, and easy access to communion makes them able to cast larger amounts of different spells. And can take advantage of things like Light of the Northern Star for stellar cascades, star fires, antimagic (an important one midgame) and other nice spells.

Without access to Elemental magic they are limited and you have to take that into account when you are building your pretender. Also I don't like the limitations of the FoB, it is nearly as easy using a VQ, GK, or Liches in order to take advantage of the VCs, while trying to give you a little elemental magic (I prefer Earth).