Is the Hex Parasite/Vampire Hexmage "remove counters from a permanent" ability still a thing? Is it still in Black?

Still in black.

Not that it matters too much, but black being able to remove counters (a la vampire hexmage) and destroying planeswalkers, are those abilities just coincidence in how they function similarly?

There are no coincidences. : ) No, but seriously, we did that on purpose.

MaRo, Suppose I might have Baron Von Count and an Everythingamajig on the battlefield. If I add a doom counter to the Baron, would it count for the Baron's ability to move from numeral to numeral? Such as either having a second counter on the 5 numeral (in-case I have two or more opponents who need doom in their lives) or on the 2 numeral (to be devious and skip numbers 3 and 4, I presume)? Or, if my opponent uses Vampire Hexmage to remove the counters, could I replace them? Happy Black Friday!

Put a counter on Baron Von Count doesn’t put it on his tracker so it has no functional implications.

It has been a really long time since Vampire Hexmage. Is removing counters in general still black, and what's the storm scale for seeing this effect again?

It is still Black. It’s not something we do a lot of but I believe you will see it again. Let’s call it a 3.

I may be wrong, but I think a reason many players don't like Hydras is because of cards like Vampire Hexmage which can automatically erase them from existence with very little effort.

Dragons are very popular and we make Plummets (“Destroy target flyer”) all the time.

Why don't we get more black cards with first strike like Vampire Hexmage

Because first strike is tertiary in black meaning it doesn’t get it very often.

Why is "remove all counters" (Aether Snap and Vampire Hexmage) a black effect? It feels like blue and green like to play with counters the most, and I can spout off a few flavor justifications for white and red, but I'm drawing a blank when I think about why the effect has only shown up in black.

Green likes to generate them and blue enjoys moving them. We figured someone ought to be able to get rid of them and black ended up getting the slot. Think of it as black’s love of killing things.