i think you might be surprized by the diversity in TS, you could run up against ANYTHING.
Legolas DH decks are very popular and if well built, very effective. they are also not much fun to play against, and in turn, they can be pretty boring to play.
don't focus as much on what you need to defend against, focus more on making your strategy work.
personally, i LOVE uruk trackers in TS. there are very few cards that completely obliterate their strategy. even if all your conditions are pitched off the board, they can still be fairly scrappy. with 4x
vengeance you can often pull a kill they aren't expecting and if played right, site 5 will be brutal.
keep in mind though, most of the strategies from FOTR block are still potent, so be prepared to see moria swarm, sauron orc tricks, if i remember right, someone on these forums had a
shadow that bombed at site 4. almost impossible to survive.