Ah, that Monster Talent supplement looks great!
One of the reviewers cites the Balor as an example of things that need to be fixed, wherein an iconic source of fear is now something you'd be embarrassed to put up against players as there'd be a letdown in defeating it. I'm of the same mindset. Any chance you (or someone on here) can vouch for it being worth the price tag (and have playtested it?)
I picked it up yesterday after reading this thread. Haven't had time to playtest it yet (obviously!), but I like it quite a bit! I'd say worth the price tag easily. A few notes:
-The Balors are great! Lots of distinctive abilities for them. The Vampire, the Aboleth, the Rakshasha and the Beholder were also big stand outs for me.
-New abilities are solid. Lots of auras, which I'm always a fan of. Aboleths are enslaving multiple people at a time, Beholders can move their antimagic beams on a reaction (brilliant, and obvious in hindsight!), Vampires charm as a bonus action (or a reaction if they're about to get hit!). If you've got three Ankhegs in a fight, one can have a harder shell with resistance, one bursts out of the ground on a recharge, and one has a spiked shell that damages you if you hit it- what would have been a dull slugfest against three bags of HP now presents some tactical decisions, and a less bored DM! Banshees and ghosts are really great too, less of a one trick wonder than they were- I'm excited to run a banshee beyond the first round now!
-There is a little bit of "now the creature has an extra attack!", which is a bit dull and we could have thought of ourselves. But, one thing I really love is the creature using it's signature move as a bonus action rather than a full action- it lets the players see whats unique about the creature, but it still dishes out the damage from it's multi-attack that it needs to be a challenge.
-A lot of creatures have abilities that let them negate damage three times- a bit like "Legendary resistance" against fighters. The description of how the creatures do this is really cool- ghosts phase into the ethreal realm and come back, frost giants make an ice wall, etc. I think my players wouldn't enjoy this feature, but the descriptions are cool, so I'll mechanically make it like a "Shield" spell which will feel more fair to them.
-"Boss" creatures have a bonus action that lets a few of their minions use their reaction to attack- I like this quite a bit, because it'll make the players a bit more hesitant to just focus fire on the leader if they know two rounds worth of attacks are coming from the smaller ones.
I recommend it, good buy, with the caveat I haven't brought it to the table yet.