I'm not sure this needs to be THAT higher than Mutant's Prey. I mean, even with Blood Feud as the most versatile version, this still relies on the opponent using that strategy to be actually more versatile than Mutant's Prey, so unless the +1/+1 counters are really, really ubiquitous, it's just going to be far worse than that card most of the time, and Prey was hardly a playable card to begin with.

I think the point is that green puts +1/+1 counters on opponents creatures, so in a green deck, this can be 2-for-1 fairly often. I'm not sure that's right, but it seems a good idea.

I support more cards in the set to encourage putting +1/+1s on the opponent's creatures.

Um; but this actually encourages you to have +1/+1 on yours, and not on theirs (and that's the right way to win the fight, too, so it makes sense)

This encourages you to put a +1/+1 counter on their 3/3 and then have it fight their 4/4. It also allows you to cast a much-cheapened, instant-speed Blood Feud against a deck that's already playing +1/+1 counters.

My first thought was that this might be more interesting if it forced creatures with counters to fight creatures with counters. It would make sense to include a spell like that, since this is one of the only blocks where a card of that nature would be printable.

That said, I can see why people would not like that version. This, after all, doesn't require you to put a counter on an opponent's creature to get value out of it.

I do find it funny that this card is worth splashing from the sideboard in block as an anti-green measure.

might be confused with Whip Vine