In light of WH3 on the horizon, many have speculated that the siege mechanics also get an overhaul. I for one hope we get racial siege mechanics, with different map layouts depending on the race that is defending.
Now it's fair to say the Wood Elves rework was pretty good. And some of the new mission maps are pretty awesome, namely Drychas Coeddil release mission. I think something like this would make for a great wood elf defense mission.
A long stretch of land, covered in trees with elevated hills and cliffs, with perhaps a few great trees that block artillery and ranged fight from afar, perhaps some rivers and other bodies of water. No walls or buildings, just natural defenses as far as the eye can see. The the invaders goal is the navigate that natural fortress to get to the back end capture the grove, while being ambushed all along the way.
Of course the wood elves need to be able to set up defensive fortifications to get a map like this, which atm they can only do with their main magical trees. While I like that wood elves don't have to invest in their settlements, I do wish they could at least build reasonable defenses in their settlements. They kinda suck at defense. Personally I hope they had a kind of reverse corruption, where they forest regrows and reclaims the land slowly. And this forestation has a number of effects, such as slowing the campaign movement of any non-wood elf army passing through it, relative to the percentage of forestation. Rendering wood elf armies and heroes invisible on the campaign map while in heavily forested areas until you get close enough, while perhaps providing additional vision from all wood elf armies/heroes and settlements in the area. And increasing the number of units settlements have for defense while in a heavily forested area. Effectively turning wood elf settlements into siege maps.
Where in short, wood elves don't so much as actively build defenses, so much as let nature take over and do most of the heavy lifting. It just takes time. We are a good whiles off from WH3, but this is my personal wish list for the Wood Elves.