@Aldhick, a few points in reply, please:
1) 15cm woods will not solve the problem. Even if hanging out the edges, the stands will still count defended. Or the WE players adopts a three-stand frontage. The key issue here is the defenders. This army has a good number (4 per 2,000) of really good (and cheap) heavy infantry (4|4|5+, no terror, no have-to-charge-humans, 105 points). If I was playing with them, they would be straight into my 30 point wood as an anchor point in every game.
2) The artillery units were charged normally by the flyers, not by the spell. They were protected by shooting chariot units. But WEs have narrow-based (and shooting) flyers, ie. best in the game. Perhaps Dwarves might have had a chance with Flame Cannons? But everyone else is in trouble and so shooting them out of their 30-point woods with artillery (if your army has them) is probably not going to be an option if the WE player is prepared to sacrifice his flyers. Which I would do every time if I was playing with them.
3) Regarding opponents' strategies, I often play against Dwarf armies. They usually 'castle-up' in terrain and, yes, you have to find ways to dislodge them. The difference is that they do not have the option to pay 60 points and get two large hills.
@Geep, also a few points, please:
4) As I said in my text, yes, the woods should have been 16cm circles. But the 'absolute killer' issue is not solved by a change in geometry.
5) As I said in my text, I tried to go round the back. But Cmd 9 ordering his Forest Spirits (no woods penalty) allowed him to easily counter such moves.
6) Yes, my artillery outranged his archers. But see point (2) above. And sending my ordinary archers (defended so 5+ to hit) within 30cm of his (3+ to hit) would have been suicidal.