I say, nice, original ideas. I like them.
Plaguesower: Could be cheaper if it hurts both players.
Tree of Life: Awesome concept, I must admit. Would be very useful with multiples of those, HevE Armor, Blessings and whatever. And the cost isn't barrierish.
Damp Out: Permanent Lobotomy, also a new concept. Good card. And I don't know if 3 or 4 Water, but I'd say 3. Deflagration can get rid of a permanent immediately for like 2 Fire, this for 3 Water makes it useless, so it's sort of the same.
Stoneweller: +2 max HP is a bit low, especially that it is a shield so you can have just one in play. I'd boost the efect to 4-5 and raise the cost to 5-6, and make it block 1 damage even in the base card.
Aether Lance: Lighting every two turns. I suggested delay as a way of balancing, and... you practically did this. Just, ability cost?