Since there's been a lot of talk about design, I want to share some of the concepts that were first discussed when these cards were designed for the first set--most of them some time ago. Feel free to change/expand on these as the Council sees fit.
Dwarves - Strong skirmishers with weapons and events. Stacking cards on conditions. Lore-wise, they are hearty so experimenting with higher vitality. Weak to conditions that play on companions, as well as conditions as a whole.
Elves - Archery and -X skirmish cards. Telepathy. Galadriel/Elrond healing allies or themselves. Condition removal. Arwen/Glorfindel strong against Nazgul.
Gandalf - Bonuses from having initiative. Strong fighter. Condition removal. Card draw. Burden removal. Limited healing. The single strongest FP character.
Gondor - Rangers. Site manipulation. Bonuses from being at sites from your adventure deck. Boromir as a strong fighter who gets stronger when injured/his opponents are injured. No condition removal. Limited archery.
Isengard - Ninja Saruman with threats/wounding. Beat-down Uruk-hai. Battleground mechanics.
Moria - Swarm. Reprints of 1E cards plus some other new mechanics. More stacking on conditions, a shadow counterpart of Dwarves in that respect.
Ringwraith - Black Breath/Blade Tip. Burdens/Resistance/Corruption mechanics. Forest Nazgul.
Sauron - Punish mono-culture decks (i.e. the Free Peoples have to band together). Trackers. Archery. Making the fellowship feel the weight of the quest (effects when moving, when assigned to skirmish).
Shire - Sneaky. Some stealth events. Skirmish cancelling. Pipes. Burden removal.
General considerations:All skirmishes can be cancelled. Not allowing the Ring-bearer's skirmish to be cancelled was a band-aid fix for bad design in first edition. Skirmish cancelling is a fair mechanic, and it's up to the game designers to make sure that those kinds of effects can't be exploited at later sites. This is totally manageable.
Limited discard and choke to promote a more positive play experience. Players should be able to play their cards. This is a fundamental design philosophy that should be carried out throughout current and future sets.
Keep expansions small to promote a constantly evolving metagame and allow for faster releases of new cards.