Expanded has many broken cards,
Greed is one that helps to keep them in check, I'd definitely run a few copies.
Shagrat, Captain of Cirith Ungol is a good early threat, and also a very good pull from
Ithil Stone and
Uruk Regular, I highly recommend trying it. I'd add single copy of
Mauhur, Relentless Hunter. Since this is expanded
Uruk-Hai Healer may worth some consideration, some of your minions (captain and regular) are always exhausted and it help fighting stuff like
Powerful Guide, Archery and all that jazz.
I'd play the full set of 4 Cirith Ungol Sentinels, in my experience, it is the stronges card for the swarm after regular. Don't worry too much about the spoting requirement, you play them in hordes anyway, I only had 4 sentries and 3 shagrat in my movie block version, and worket prefetly fine.
I really dislike
Uruk Soldier, too easy to kill with cards like
Greenleaf or
Aragorn's Bow, or
Powerful Guide, you don't want to lose a minion from your swarm for only one activation of those cards.