I have been trying to play solo some lately and I am having a lot of trouble. When playing with 2+ players I have not lost yet (to be fair I've only played about 4 games with multiple players and mostly Mirkwood) but solo I can't seem to win. I failed Anduin about 4 or 5 times yesterday with at least 2 different decks (dual sphere and triple sphere).
What I've noticed solo is that it is difficult to be able to do everything yourself. The best I've come up with so far is that I need to have each of my heroes fill a specific role... 1 for offense, 1 for defense, and 1 for questing. Even with Denethor defending with Protector of Lorien on him I was having trouble due to multiple enemies at one time.
When building dual sphere decks I have trouble fulfilling all roles with only 2 spheres. I was originally playing a Tactics/Lore deck, then switched to Tactics/Spirit, and then I tried a Leadership/Spirit/Lore deck. I have built a Spirit/Lore deck with very low starting threat and Dunhere for hopefully making combat a bit easier, but I haven't had a chance to try it yet.
I've also noticed that some things don't scale quite as well... such as in Anduin when I am having to flip an extra card each turn. I can get to this phase pretty quickly using Gimli and Legolas, but my heroes are beat up and end up dying to a treachery or shadow card while I struggle to keep up with questing as I'm flipping 2 cards per turn.
So, how do you deal with being able to fulfill all the roles with a single deck? Should I forget about a defense hero and potentially have lots of throwaway allies I can use for defending and then counter with some more powerful heroes? Should I try and use low threat heroes so I can have enough time to build up some allies and attachments?