Interesting that it is proficient with Dexterity and Wisdom saving throws. 

So they don't have HP Regen anymore?

No they don't they have increases AC and HP to make up for it. They also make 3 attacks now instead of 2. And they gained a really great bonus action.

I noticed they increased the HP by 8 and the AC by 1. The damage and mobility is interesting but I must admit I am sad to see that ALL vampires lost regeneration. It added to that vampire flavor, but mechanically it isn't terrible I suppose. Kinda like removing werewolves needing silver and adding about 8HP. I sorta get it, but I also understand why people hate the werewolf change.

For me it's one of those things I'm sad to see gone but I'll still try the new blocks before casting full judgement.

Note that Vampire Spawn no longer are bound to server the vampire that created them, though they could still do that if they wanted to. 

Quote from Princedg5678 >>

Note that Vampire Spawn no longer are bound to server the vampire that created them, though they could still do that if they wanted to. 

They will if they know what's good for them.

Failed to put Regeneration on them. Guess I'll have to make an edit. Zero reason for them to remove a feature in every lore ever written about Vamps. 

Multiattack. The vampire makes two Claw attacks and uses Bite.

Can someone please explain how this works exactly? Vampire gets two Claw attacks, and then if successful on a hit, it then gets to Bite? And they can do this every turn?

Playing Strahd and a group of Spawn killed the whole squad!

Yes that is how they are designed to work. The new monsters are meant to be a lot more threatening, and my group concurs. We have been enjoying these more deadly monsters in our games!

I'm confused. On the Bite attack, it has a Con Save, and only describe a failure, not what happens on a success. Or am I missing something?

"Failure:" describes the effect that occurs on a failure. If there is no failure, there is no effect.

Regarding the question about attacks. The vampire uses two claw attacks and its bite attack. The bite attack can only target a creature within 5 feet that is (1) willing, (2) grappled, (3) incapacitated, or (4) restrained. If nothing satisfies any of those prerequisites, then the vampire cannot use bite because it lacks a valid target.

Does the target's hit points maximum reduction not recover after a long rest like the previous Vampire Spawn?

They moved the line explaining that to the Long Rest Rules, 

"Regain All HP. You regain all lost Hit Points and all spent Hit Point Dice. If your Hit Point maximum was reduced, it returns to normal."

Shouldn't the grapple escape DC be 14? 

Grapple. The target must succeed on a Strength or Dexterity saving throw (it chooses which), or it has the Grappled condition. The DC for the saving throw and any escape attempts equals 8 plus your Strength modifier and Proficiency Bonus. This grapple is possible only if the target is no more than one size larger than you and if you have a hand free to grab it.

- https://www.dndbeyond.com/sources/dnd/free-rules/rules-glossary#UnarmedStrike

There’s a lot of weird errors or vagueness in this stat block. Really needs a second draft.