I'll chime in here.
1. The whole thing with goblins, etc being incredibly weak is a bug, or at the very least an oversight resulting from armies actually existing rather than just sort of popping into existence on your doorstop. Commenting on the difficulty of DF2014 goblins isn't really logical since their weakness results from several mechanics that (probably) aren't quite working as intended.
2. I agree with the notion that zombies should remain incredibly threatening. Any person who plays adventure mode (or pays attention to combat logs at all) knows that soldiers are rarely felled because they were rendered incapable of being alive or fighting due to organ damage; they die because they feel pain, they get tired, and they bleed. Simple removal of those things is enough to render almost anything into a dangerous killing machine. Think about how much damage a simple house cat could cause to a fully grown human if it didn't feel pain or immediately die/fall unconscious upon having a limb crushed or removed.
3. Undead are still -absurdly- powerful. I understand giving them slight buffs to strength, since your physical power is in part limited due to the fact that you feel pain. But the massive increases in strength on top of the most important stat in DF (agility) makes them ridiculous. They are outrunning (and therefore outfighting) ridiculously strong modded adventurers consistently. To take a peek at this particular creature's stats:
[BODY_SIZE:12:0:360000]
[PHYS_ATT_RANGE:STRENGTH:1000:1300:1550:1900:2300:2550:3000] +++
[PHYS_ATT_RANGE:AGILITY:450:950:1150:1250:1350:1550:2250] +
[PHYS_ATT_RANGE:TOUGHNESS:450:950:1150:1250:1350:1550:2250] +
[PHYS_ATT_RANGE:ENDURANCE:450:950:1150:1250:1350:1550:2250] +
[PHYS_ATT_RANGE:RECUPERATION:700:1200:1400:1500:1600:1800:2500] ++
[PHYS_ATT_RANGE:DISEASE_RESISTANCE:50:150:600:800:900:1000:1100] --
[MENT_ATT_RANGE:INTUITION:450:950:1150:1250:1350:1550:2250] +
[MENT_ATT_RANGE:FOCUS:700:1200:1400:1500:1600:1800:2500] ++
[MENT_ATT_RANGE:PATIENCE:50:200:400:600:800:1000:1200] --
[MENT_ATT_RANGE:MEMORY:450:950:1150:1250:1350:1550:2250] +
[MENT_ATT_RANGE:SPATIAL_SENSE:700:1200:1400:1500:1600:1800:2500] ++
[MENT_ATT_RANGE:KINESTHETIC_SENSE:700:1200:1400:1500:1600:1800:2500] ++
[MENT_ATT_RANGE:EMPATHY:150:600:800:900:1000:1100:1500] -
[MENT_ATT_RANGE:SOCIAL_AWARENESS:150:600:800:900:1000:1100:1500] -
On top of four arms flagged with independent multiattacking, i.e. five free attacks in one turn without penalty. Undead overpower and outpace a creature at the very top of these ranges at adult size. (I should mention that this creature's attacks are so powerful that you're better off simply punching things to death rather than using a weapon, as said punches are capable of removing limbs from basically anything smaller than you.)
4. 40.24 combat seems broken in general. A dwarven adventurer who was a legendary fighter dressed in full steel, with artifact steel mail shirt was easily disassembled by a simple spearman, if I am remembering correctly. Bogeymen remain as stupidly powerful as ever, shattering skulls with single punches despite being a couple inches tall. It's impossible to tell hostiles from friendlies, and even successfully doing so still gets you branded as a murderer.
5. Speaking about 1v1 situations with undead is absurd. The smallest group of undead I have ever encountered in any mode was around 40, from a necromancer siege.