I don't find
Vindicate to be the auto-include it once was - when I'm paying more than 2 for removal I really want that instant-speed flexibility. Now, that's in different colors with tons of competition for premium single-target removal and new amazing removal spells every year, whereas green is the worst removal color in MtG. Even so, I've never run this since by the time I was into EDH
Beast Within was a card and I rarely run mono-green.
I wouldn't turn my nose up at a mono-green player still running this - it's cool, it's fun, it's simple and effective. But as everyone has already noted -
Scour from Existence is one more to be at instant speed,
Introduction to Annihilation is one less (but it gives them a card). If budget is no concern, there's also powerful 'walkers like
Karn Liberated and
Ugin, the Spirit Dragon or powerful auras like
Song of the Dryads. You're also at the cost that you could just run straight-up boardwipes like
All Is Dust.
Oblivion Stone, and
Ezuri's Predation for a little more or less.
Also also - this is most often run to have an answer to creatures, since mono-green has access to stuff like
Acidic Slime,
Woodfall Primus,
Bramblecrush, etc to deal with non-creature permanents. But in green, if your creatures are big and reliable enough you can just run fight cards. At the dawn of EDH we had the fine staple
Prey Upon and reusable
Ulvenwald Tracker; since then we've got plenty more incredible cards like
Ram Through,
Thorn Mammoth, and
Kogla, the Titan Ape. While these aren't as reliable as just straight-up murdering a creature with the power of wind, they are still where I'm gonna be looking in most EDH decks.