Would this be better as a 1/1 deathtouch similar to Typhoid Rats rather than as a less painful Carnophage?

Could be. Nowadays black gets a plethora of 2/1 for one, although usually at uncommon. I do not feel that the drawback is necessary. It will probably be better as a vanilla 2/1, or a 1/1 deathtouch.

Black's 2/1s still have downsides.

And they're not usually at common. Also (abt raptor's suggestion) they don't usually just make colorless deathtouch creatures in lower rarities. I think they don't want to bleed that ability into colorless too hard. I suspect a 1/1 deathtouch would be a godsend for a lot of decks (especially in a set with artifact death themes).

Does this HAVE to be a one-drop? I still say a black 2/1 1-drop with upside is not a common card by any definition. It could easily be a 2/2 for

Slight mistake in the card text but the card looks cool now.