I may be in the minority, but I'm not sure they current rules for Woods are a problem. Sure, standing at the 'edge' of the woods isn't an asymmetric to-hit-mod situation like it is in TW, but I don't think that is necessarily a problem that needs to be fixed. As it stands now, Woods are a purely defensive piece of terrain. You hide in or behind them to add that +2 to anyone shooting at you, but in return, you sacrifice the same +2 on your hits. So, it is something us use when it is more important not to be hit. Partial Cover, on the other hand, is something you try to use when you care about landing hits yourself. Partial cover only works from one angle though. Usually, you can't find a pit to hid in that gives you partial cover from all directions, so it leaves you open to flanking attacks. Woods don't. You get that +2 no matter where the incoming fire is coming from. Personally, I LIKE the distinction between the two. The to-hit mod is the same, so you don't have to worry about remembering which one is which, but the reason why you would seek out woods or partial cover is different.
I do see a lot of firing lines behind partial cover these days, so I'm willing to be convinced that it is now too powerful, or that woods need to be less punishing. However, I'm not totally seeing it. Finding cover to fire from was an important tactical part of TW, so I'm not certain it is a bad thing that people are seeking out cover to fire from in AS as well. I certainly got caught by this in the one segment of Scotty's AS campaign at GenCon I was able to make it to. We took positions in the woods trying to move up, but didn't take the hills for partial cover and ended up paying for it. On the other hand, I was able to use woods to help keep a Black Knght alive way longer than he had any right to be, so they still worked well when used correctly.
Now depth 1 water? That is like super-partial-cover which works from any angle or direction! Depth one water is the best cover there is, in my opinion, and I'm all for doing something to make it less awesome. Adding a crit roll in some fashion when you take hits in water would be a good thing. I'm not sure if it needs to only happen when structure is damaged or not, but I think it is a good idea to work with.
As for Woods vs Partial Cover. If you were going to add Damage Reduction to anything, I'd say add it to the woods. I think that does more to balance the two than reducing partial cover to +1 and adding DR to it. It seems like the basic problem is this: if I am in woods and you are not, but have partial cover, it is currently +4 for me to hit you, but only +2 for you to hit me. You have a +2 to-hit advantage on me. Now, if I stand out in the open, and you have cover I am at a +2 and you are at +0, so you STILL have a +2 to-hit advantage on me. Unless I don't care about hitting you and just want all the defense I can get, Woods loose vs. Partial Cover. If you see this as a bug and not a feature (which it may be), then you want to either narrow that gap, or add something to the woods that Partial Cover doesn't have. Here is what I see happening:
- Reduce partial cover to +1 and add a DR to it: Well, the to-hit gap is smaller, but still in favor of partial cover, and now partial cover reduces the damage of any hits that land as well. Partial cover still wins.
- Leave the mods alone, but add DR to woods: Partial gets the to-hit advantage, but you better hit hard because Woods are now like the SHLD special. Now, if you manage to line up partial cover AND woods, you are king of can't-kill-me hill, but that's not always real easy to line up or maintain. Partial cover may still be better.
- Make woods grant partial cover: Instead of being a separate thing, just have woods grant partial cover for any shots going in or out. Now, it doesn't matter if you are outside the woods hiding behind a hill, you still only get +2 because whether it was the woods or the hill doing it, you can only get 'partial cover' once. I get +2 at you, you get +2 at me, it's all even and doesn't stack. Sitting inside the woods would still be somewhat undesirable because you would be giving partial cover to anything you choose to shoot at. Partial cover would still be good because it will give you that differential +2 against units out in the open. The idea here would be that hiding behind stuff is a flat mod, regardless of WHAT you are hiding behind.