Well I just got enough dust today to buy Thalnos, and I must say he doesn't feel that great.
In about 10 games I played, I only used his +SP effectively once (with lightning storm, to boost it to 4-5, where the minion was at 4 health, so it went from a 50% chance to 100% chance to kill).
Other times, he just sat in my hand.
When I had no nuke spells in hand (lightning bolt, lightning storm, lava burst, earth shock) and I was top decking, I wasn't really sure whether to just throw him on the board and draw a card off him, or whether to keep him in hand in case a nuke spell came up. (?).
Eventually if I used a lot of my nukes already I would just throw him on the board to die. Is that what everyone else does?
In any case he is a bit underwhelming (imo) and not so reliable to draw when I need him (since there's only one of him) and so I'm wondering if I should take another card instead, like wind fury or ancestral spirit.
Perhaps a second lightning bolt would even be better than thalnos? (only have one).
Other legendaries in my deck are Cairne and Al'Akir.
My draw cards are 2x mana totem and 2x azure drake.