I would consider adding minions like
Foul Horde (
5R50) that can actually win skirnishes against high st companions intead of the st 5
warg rider.
The point of your deck doesnt seem to be bombing opponent, instead of this playing 2 or 3 fierce minions that will win their skirmishes and cause some damage. For an average swarm to be efective you need at least 6 or 7 minions at one time which i think you could hardly launch with that many non-fighting cards.
i dont know if saruman is also needed, since you have 6 wargs and 4 copies of
warg-master which seems enough to play your mounts, and he cost 4 which can make you unable or to play him or to play more stuff (minions, events)...
For start i would change a bit your minions with something like this:
add:-
Foul Horde (
5R50) X2
-
Sharku, Warg-captain (
5R58) X2
-
Isengard Rider (
5C53) X2
remove:-
Warg Rider x4
-
Isengard Flanker x2
If you don't plan to add some
Isengard Axe (
3C55) i would remove Saruman and add one of the following minions:
Orc Overseer (
3R65),
Orc Commander (
3R64) or even
Isengard Mechanics (
6R68) for some extra crowd control since big companion swarm like ents can't be stopped with just 2 copies of Enquea. If you really like Saruman and wanna keep him i would make the following changes:
- add
Isengard Axe (
3C55) X3 (adding pool is great for your deck and makes your guys bigger, also helps to "reduce" the cost of Saruman when you play him)
- remove one copy of
Saruman's Snows;
Isengard Warrior and
Warg.
I think the deck idea is nice, if you keep improving it you will have a shadow with at least a good stopping power. Since it's a deck that can use
Saruman's Power (my favorite card) maybe i will try some version of it

Let me know when you do some playtesting...