Thanks for detailed input Mav.
To answer the first question, since this is a more mage-centric build, I value sweeping a lot, mainly to get past guards and even the odds against an opponent with more creatures than me. I could run other ways to get around guards, but those ways are more easily dealt with than a creature. Corazin is pretty much just a big Kriegsbiel that is equally good against single targets. Butchers are there as a cheap way to gain dice and they'll survive for a few rounds. Alchemist helps do whatever, including take on fliers, but you're right that I could stand to include more ways to deal with them and Grimson and Ludwig were already high on my list for that.
Flank Attack I took out even though I'll mourn the loss of cool goblin art, but Sniper Shot feels pretty essential to me. I don't know if it was GenCon or something else, but I'm running into a lot of Reverse Attacks, and having a way break them at key moments is important if I want to use Hurl Boulder but suspect a trick. The amount of value someone can gain from RA is pretty stupid, so 1 point to prevent that and defenses/Block isn't a big price to pay.
You're right about the weapon count, I cut a Morning Star. Elemental Cloak instead of those 2 armors is also probably a better deal. I think being well-prepared against defenses is justified, though; some of the best creatures, like Gremlins and Knights, are just too unapproachable without having a plan for their defenses. Falcon Precision also gives your Sledge 2 unavoidable piercing +1 (with Rune) attacks with a solid chance to daze, which helps your other creatures get hits too.
The Arc Lightning is there mainly for Brogan Bloodstone. He counters 2 of the Warlord's runes (armor and defense) and has been a major problem for me in the past. It's also good against the holy Knights. Basically, I play against a fair amount of priestesses both IRL and online, so a often repeatable 5 dice attack for 4-5 mana seems justified to me. Flameblast/Hurl Rock is usually how I deal with fliers, but that could not be enough.
Finally, I find it hard not to justify Enchanter's Ring with the dwarf. It costs pretty much nothing with the Forge Hammer and Battleforge, not any mana from the mage's mana pool at least, and starts netting mana after the first enchantment. It actually seems a little better with the Warlord than the other mages, but maybe I'm missing something.