I agree: get Aragon on a horse with armour---unless the Isildur's Heir special rules are worth it to you. Put your Rangers of the North on horse as well, and Forlong the Fat. A sprinkling of cavalry come in so handy for so many scenarios. Drop Halbarad. Blackroot Vale archers have a reroll aganst monsters, but can't have spears, if I remember... stick with your Rangers. I'd suggest:
Strider w/ armour and horse
3 RoN mounted
12 Rangers w/ spear
Forlong on Horse
15 Knights of DA on foot
12 Pikes (Men of Arms)
1 Ranger
700 points 45 units 9 (or 10?)+ might 13 bow
Or trade Aragorn for Halbarad and get another 10 units: 20 elite shields and 16 Ranger bows...
Oh...download a LOME armybuilder:
http://lonelyknight.0fees.net/ Enjoy!