I need to try Harshforge, but I don't like the look of it. It's an anti enchantment tool, and the Warlord needs something in that department, but I'm not a fan of mana denial as a counter to a specific type of strategy, as it narrows the optimal strategy. I particularly dislike adding Upkeep to a whole class of things.
At least other mana denial cards leave you room to work and take time to be efficient plays most of the time. With Harshforge, I suspect you can often break even on mana the turn you play it in many matchups, as catching 6 enemy enchantments in it's area of influence is not unreasonable. And then it's extremely tough for it's cost, making killing it potentially a full round of effort, even without protection from guards. Even with adjusted play, and using fewer enchantments, many builds will want to use at least 3 enchantments at a time.
On the other hand, this will make command incantations much more on par with enchantments with similar effects.
Harshforge looks extremely good for the Warlord and Necromancer. Possibly for the Wizard as well, although it will weaken traditional telepit plays based on Enchantment Transfusion, Jinx, Nullify, and Force Hold/Force Crush. Still, you can often get the important aspects of that type of play to work fine with Teleport spam anyway, so...