Does butchering a wood and metal forgotten beasts produce logs and ores?
Yes. I'll add testing this to my todo list, because it's been a long time. I really wish I could make bronze collossi drop statues of themselves rather than random statues, but I doubt that's possible without dfhack.
Do these combat changes make the game easier or harder?
It's complicated. I prefer a harder game if possible (checking and testing the harder farming mod is also on my todo list), but many of these changes weren't made "to make the game harder". I'll be looking into consolidating and removing layered armor, but that will take some testing (and will make the game harder, because armor layering is cheaty nonsense).
elves siege and wield betterand more sensiblewooden weapons. (Coherent Weapons)
This definitely makes the game harder, unless you're playing as an elf in adventure mode. The weapons elves wield in vanilla, however, simply don't make sense. They're using "regular weapons, but shitty because they're made of wood". The weapons they wield in Revised make more sense as wooden weapons (clubs, for example). This is as much for flavor as it is for balance. Players shouldn't laugh off elf invasions. Dwarf Fortress elves are already reasonably unique in terms of lore. Personally, I think the new weapons suit Toady's vision for them better than their old weapons, but I can see why this would be a controversial change.
There's a bit of hand waving here, as their "hardened" wooden spears are much better than regular wooden spears, but that's easy to dismiss as being a culturally guarded secret. Some mods use magical wood here, but I prefer my approach. It'll also continue to make sense after the magic and myths update, but magical wood won't.
I'm considering elven wooden armor for an update, it's on the todo list. No idea if I'll go through with it. Probably not, because tiered leather is also on the todo list.
long swords aren't easily used one-handed, but they slash better. (Coherent Weapons)
Neither harder nor easier, weapons are used by both dwarves and invaders.
large spiders and spider people that couldn't trap with their web now can. (Modest)
Definitely harder, unless you happen to be playing one of the spider people that can trap with their webs. (Does adventure mode let you? Would be fun to test.)
scratch attacks without claws or talons have been removed. (Grimlocke, Revised)
Neither harder nor easier, this affects all the main humanoid races. Combat just makes a bit more sense. A change in v1.5 that I didn't bother mentioning is that bear people can now use nail scratch attacks, even though it's not a talon attack. Because bears. I'll be going through the files and giving nail scratch attacks back to more animal people that thematically have long claws.
many animals and humanoids aren't as flighty. Predators are fearless. (Wanderer)
Definitely harder. Things just won't run from you as easily in Adventure mode, and will be more willing to fight to the death in Fortress mode.
scimitars are big and powerful, with a wide contact area. (Coherent Weapons)
Neither harder nor easier, weapons are used by both dwarves and invaders.
bows and crossbows are weaker and differ from each other more. (Wanderer)
Neither harder nor easier, weapons are used by both dwarves and invaders. On the todo list is adding a reaction to make arrows in fortress mode, but I need to take stock again of just
who uses bows now. Pretty sure elves use spear throwers exclusively now (for ranged).
bone doesn't feel pain, and fat and muscle feel less pain. (Wanderer, Modest)
Neither harder nor easier, this affects everyone. Just makes combat and injuries make more sense. I suppose this makes it easier in Fortress mode whenever you're fighting something without bones, fat, or muscle.
whips have been weakened and cost more to create. (Coherent Weapons)
Easier, unless you're in adventure mode wielding a whip. Whips aren't usually used in fortress mode but were overpowered before. The cost change here is the part of Coherent Weapons I'm the most confused about (I don't know why it's here), but I trust the author here. Might be worth looking into on the todo list.
Really, whips aren't weapons at all and never have been to my understanding (to any great degree). This is more D&D nonsense. It's a tool for controlling and hurting people and animals (or being kinky, apparently). I was tempted to remove whips entirely but that seemed unnecessary. If whips are too weak after these changes, then good riddance. That's what goblins get for using a stupid weapon. (I suppose I should add rethinking a whip replacement to the todo list).
short swords and spears have smaller contact areas. (Coherent Weapons)
Neither harder nor easier, weapons are used by both dwarves and invaders. Come to think of it, I should confirm that this change also applies to the elven spears.
long swords can now be gripped partly by the blade. (Coherent Weapons)
Neither harder nor easier, weapons are used by both dwarves and invaders.
some insects have more accurate and more varied colors. (Warlord255)
Misplaced line. No affect on combat whatsoever.
giant predators eat dwarves, and many ambush prey. (Modest)
Definitely harder. This is a significant change. They'll be
a lot more dangerous creatures in savage areas. I'm not sure if so many of them need to be ambush predators, though: I might look into that.
renamed body parts for more legible combat logs. (Modest)
No affect on combat whatsoever. Only better reading. An upcoming version will have some additional bones added (for good reasons, not just because), that will affect combat and will need to be tested.
skulls are sturdier and skin is thicker. (Wanderer, Grimlocke)
Neither harder nor easier, this affects everyone. Easier, if you're facing something in Fortress mode that doesn't have a skull or any skin. Hopefully, this change alone is enough to balance combat better.
short swords penetrate more. (Coherent Weapons)
Neither harder nor easier, weapons are used by both dwarves and invaders.
many tissues now heal naturally. (Modest)
Easier, because the invaders will be dead or will flee, and who cares if they heal slightly better off screen. Fewer dwarves should need medical treatment for minor wounds. I need to take the time to rewrite some of these lines, as this is poorly written: this just makes hair, nails, horns, and more heal naturally (but slowly).
many giant creatures can bite. (Modest)
Definitely harder, as you can't play as a giant creature and bite attacks are broken (overpowered). I don't think Toady will fix bite attacks even when he revisits combat, because he seems proud of stories of dwarves biting off limbs and carrying them around in their teeth. If a dwarf can bite off a limb, you can bet a giant lion can do worse.
most humanoids won't bite. (Revised)
Neither harder nor easier, but combat makes a lot more sense. Arguably easier, if you're playing as a bird person or a bug person in adventure mode, because now you enjoy a strong attack that most of your opponents won't have.