My take on the new cards:

Leadership Eomer's ability is only good with enemies in the staging area, so aside from Fastred and Late Adventurer may be a rare thing. His questing value is low, so unless he can eliminate an enemy in staging it's unlikely to be used. With 3 attack and 10 threat he matches Amarthiul for the cheapest attacking hero in Leadership, so even if his ability rarely kicks in he's still a decent hero for the sphere. Rohan doesn't have many leadership allies, so I ordinarily wouldn't put him in a Rohan deck...

However, Guthwine is awesome in a Rohan deck, enough so to justify leadership sphere for solo Rohan. However, I think Theodred/SpTheoden/Eomer would make a better base.

Tactics Elfhelm's ability makes him a when-needed chump or source of 1 wp or 2 attack, but he's not that exciting at full price and his spirit cousin is. I don't see him as a Rohan deck guy, I see him as a splash guy in decks with Rohan heroes used for utility rather than trait, and there's a lot in that category (Theodred, Grima, Eowyn etc.) . He combos especially well with TaEomer and LeImrahil, though the later is non-Rohan.

The new Elfhelm is awesome! He's like a Ranger of Cardolan but with more windows to jump him out. his high printed cost could actually be a benefit if you use him with A Very Good Tale.

True, excellent with Very Good Tale. Ranger of Cardolan is a good comp, though I think more attractive at full price -- non-unique, neutral resources, and better willpower.

Another point for the Ranger of Cardolan is that you can use his attack or defense stat when you pop him in and, assuming he survives, still AVGT with him in the refresh phase before he disappears. Not so easy with Elfhelm. Still, his timing flexibility is indeed nice.

I don't think he'll topple Dunhere as the staging area attack king, but I could see some potential in him riding Firefoot and killing both a staging area enemy and an engaged enemy in one blow. He's also the best case for using Grappling Hook we've seen so far.

Just realized that Eomer has an interesting interaction with Battle-Fury. Pay your 1 tactics resource, get an attack on an enemy engaged with you (let's assume Firefight/Spear of the Mark for 6 attack against an enemy engaged and 7 in the staging area). Then somebody on the table pays a spirit resource, and Eomer commits to the quest, getting a second attack at 7 or so in the staging area. Two resources to attack twice and commit to the quest. Seems like an interesting combo to me. I'll have to get it on the table to see if it's worthwhile, but there might be something there.

I'm looking forward to using Leadership Eomer. I'm a sucker for attacking enemies in the staging area. Great art too. I just wish they hadn't cropped out the part showing the sword sticking out the back of the orc...