This is my third time playing SOA/TOB, but have yet to play solo. It is something I will definitely do when I finish my current game and after I have my exam in june. It is definitely very challenging and prolong the game replayabliity.
However, I also suggest you to play a multi-player game so you can get a feel of what all the other classes can do. Try a monk, archer, priest of talos, f/m/t, bounty hunter, blade, stalker, undead hunter, swashbuckler, cavalier, kensai, wizard slayer, avenger, assassin, sorcerer, shapeshifter, kensai/mage, wizard slayer/thief, cleric/ranger, fighter/cleric, cleric/mage..... There are just too many games to play if you play on single player.
Sorcery and Shadow together as one, the arcane and the dark united. Through our knowledge and skill none can stand against us. We are as one, infallible and invincible. The Shadow Mages.