I built this deck to counter tempo and midrange decks, specifically Tempo Rogue, which I think is the most powerful deck currently. The reason Runeforge Haunter is in the deck is to get extra value out of your weapons. Even if it only gives you one extra durability, it is usually still worth it, especially if your weapon is buffed. I feel that you are getting more value per mana this way.

I just felt the deck could use a little more late game.

Thank you!

The reason I put Beneath the Grounds in the deck was to counter Reno decks, so they could not pull off their combos. This works even better when combined with cards like Mimic Pod and Valeera the Hollow to allow you to block their combos for the entire game, but I understand your confusion. If you really want to switch it out, Tar Creeper is a good replacement.