|Neil Spicer RPG Superstar 2009, RPG Superstar Judgernaut, Contributor|
...most of my PCs are martial (paladin, fighter, gunslinger, ranger and alchemist), and pretty much all of them have ACs around the 23-24 mark, so CR4 Spriggans with +3 or +4 on their attack rolls are not going to touch them.
Looking back, I wish I could have addressed this concern. Lots of folks commented that the spriggans wound up being pushovers due to their inability to hit the ACs of 7th level PCs. Sometimes, I wonder if that's because folks have optimized their PCs by having ACs above the norm? From a game design standpoint, the Fellnight spriggans were established as a reasonable CR 4 threat. And, in numbers, they should have still made for a decent encounter for the APL of the 7th level PCs. Regardless, maybe they could still be ramped up a bit with the Advanced simple template, a class level or two, etc.
I'll likely swap out the Assassin Vines for a Tendriculos, for example, since they're more Fey related anyway. Any other ideas for changes would be good!
You may want to consider the mythic assassin vine from Legendary Game's Mythic Monsters: Plants PDF. That should put some fear into them.
My two cents,