Hobgoblin Warrior

Can you please tell me why the sword is awesome in this humanoid's hands , and crap in mine ? 

This breaks the realism in a fantasy world rule in DnD surely. 

I'm sure it's fine to give a creature that attacks at advantage a 4d10+1 (5 to 41) damage crit. 
And I'm sure it's also fine to make an armored warrior a glass cannon that does 3-21 damage on a normal hit, when you may be facing a level 1 to 3 party. 
I don't know why they made some creatures so swingy and crit-nasty.
Knights using crossbows now make 2 attacks at 2d10+1d8 damage, (3-28), but only +2 to hit, like they're spraying AK47s. 

Overtuned as hell ah cr 1/2

I don't like the idea of a basic hobgoblin grunt having half-plate and I really don't like how 5e's monsters just play by a completely different and laughably handicapped set of rules compared to players, with martial npcs just having inflated damage dice for no stated reason which only serves to accentuate how outclassed martial pcs are by their peers and their foes alike. But I also just noticed this guy's wearing striped pants. I like that. It's probably the only aspect of this design that I enjoy. They should be even more colorful and ruffled like no tomorrow. Hobgoblins should be evil landsknechts except with a uniformity to their bombast to reflect their lawful tendencies.

They don't, but they should. The arbitrariness of it causes a world that makes no sense and is internally inconsistent. Someone needs to slap the MTG folks' hands and give the reins to someone with a bit more sense of story, who understands the importance of believability (yes, even in a fantasy setting). 

Why would a medium sized humanoid with a strength of 13 do double a weapon's typical damage? This is what happens when the MTG folks (or worse, the 4e folks) get their hands on things. IF there's going to be that much of an insane difference in the damage they can do compared to any similar species in the PHB (or even Hobgoblin Player Characters as outlined in Monsters of the Multiverse), give some explanation as to WHY. I get the idea that the math has to work, but the math should serve the story. There's a lot I like about 5/5.5 but this kind of thing makes me pull my hair out. 

I get that monsters should hit harder and be more challenging for players, but this is ludicrous. I would nerf the longsword damage to 2d8, and the Poison bow damaage to 2d4. This could literally insta-kill a level 1 Wizard, or even a different class. 

My experience as a player against this lil guy: I roled as a 1st lev paladin (17 HP), entering a dungeon with light on my shield, I failed the perception check so I could't locate the Hobgoblin Warrior at the end of a corridor. On his turn the lil guy attacks with the longbow and CRITS! That was hilarious!
Rolled damage: (2d8+1: 3+1+1) 5 dmg (Wow, I have luck!) and then (my surprise!) 6d4 poison damage (15 dmg tot): 20 dmg, Paladin dead! And the fight hadn't start yet!
Ok, the party took care of my corpse... but that was pretty impressive for a CR1/2!

I ran this monster against a party of level 4 in Lost mines of phandelver. 
I'd even given them more loot than the base adventure so they were higher geared then the adventure is balanced for. 

I didn't pre-math these guys as I rolled them up on the random encounter table. Thankfully the party was fully rested AND spotted the ambush when 5 of these attacked. 

One got a crit on a player with his longbow and one shot them to U/C

2 other players went down too and it's just lucky they have plenty of healers to yoyo them back up. 

This fight was on par with them chasing down and finishing off Venomfang at level 3 and only worth 125 XP each? Unbalanced AF. 
I really don't like "pulling punches" on my players as I want them to feel like they earned it, but I'm going to award them more XP after looking at the legacy version differences. 

Okay, why haven't they fixed this thing yet??  2d10 + 1 damage with a Longsword?  Really?  And 3d4 extra Poison damage with its Longbow attack on top of already doing 1d8 + 1?!

To consolidate what others have observed:  It's using a Longsword, which should be 1d8 (or 1d10 if using two hands--but then it can't benefit from extra AC provided by its shield).

And how did they come up with the 3d4 Poison damage for the bow?  I feel like at the most it should be an extra 5 (2d4) Poison damage.

Since this is only a CR 1/2 creature, I honestly feel they missed all of this in their QA process.  Whoever did the Longsword damage was probably thinking "Versatile gives an extra damage die on top of increasing to the next higher dice," which it doesn't (it just goes from 1d8 to 1d10).  On top of this I feel they forgot(?) that it carries a shield, so it shouldn't matter anyhow (assuming it actually uses the thing they added to its Gear list).  It doesn't state that it's not using its Shield, so the Versatile factor is moot unless you throw some variants at the party that decide to doff their shields.

To fix it (and still keep it as a CR 1/2, which is needed for fighting "low-level" fodder), I'm going to adjust the Longsword attack to 1d8 + 1 and reduce the Longbow's extra Poison damage to just 5 (2d4), which is still high but not necessarily TPK high.