I love the idea. It's very interesting, and looks like it would make for some really fun encounters. I just have a couple of suggestions. These are of course purely in my own opinion...so if they don't strike a vibe with you, feel free to just go "Uggghhhh!" and try to scrub the memory of reading this post from your mind...
Skill-linked monsters are monsters that appear in greater numbers, but can be defeated in swaths by skill checks. At the beginning of each encounter, the DM should make it fairly obvious that skill-linked minions are present and how they can be defeated. The system works best when you replace two or fewer standard monsters with skill-linked monsters.
First, I'm not sure what you mean by
"at the beginning of each encounter, the DM should make it fairly obvious that skill-linked minions are present and how they can be defeated." If you simply mean
"tell your players that there are skill-linked monsters present, etc...", then I'm not a fan. If you instead are suggesting a DM say something to the players like
"you see a horde of xxxxx in front of you - mixed in with this horde are two spirits of fire, the likes of which you've never seen before - something about them reminds you of something you read once...", or something similar - and then having characters with the appropriate Knowledge Skill make a Skill Check to see if they know the monsters skill based weakness - then I'd say
"Sweet!".
Just as I'm not a fan of telling Players
"you're in a Skill Challenge...", I don't like the idea of just telling players these monsters are present and how to defeat them. I prefer such knowledge be imparted through in-game roleplaying.
Secondly, I love the idea of alternate forms of resolution in a combat encounter...but not to the exclusion of combat. I'd suggest that for monster types (not just flying books, etc. - more akin to your fire spirit example), that such monsters should be able to be defeated by either a skill-linked solution
or a combat solution. Even in Skill Challenges, I'm not a fan of the
"one road to success" scenario. Just like with clues, dungeon exits, etc., I try to follow a guideling of always providing at least two different, but preferably three, ways to success in any given situation. Using the fire spirit example again, this means that everyone in the group is capable of effectively fighting and defeating them, and the monsters can still be defeated even if nobody makes a successful Knowledge Skill check (to figure out the skill-linked solution). If there are a horde of skill-linked monsters, then treat them as minions as pertains to using combat. If less, scale appropriately.
Aramax's scenario sounds like something best resolved through a straight-up Skill Challenge (using whatever Skill Challenge rules one prefers, whether RAW, Stalker0's, or another). I would present the book scenario as
"suddenly and by the score, the books lining the walls shelves begin flying about the room - there are just too many books flying at you from too many directions to be able to "fight" them - you're going to have to find another solution..." At that point, the Skill Challenge starts, though it doesn't need to be specifically stated as
"You're in a Skill Challenge...". Though, as with my above advice, I'd still let players
"swing away" at them if they wanted to. It would just mean that for that round they defended themself from the books by attacking, avoiding any damage to themselves that round for a successful attack...but not necessarily furthering the groups success as pertains to the Skill Challenge.
The skill-linked ideas you came up with (like using the Arcana skill to cut-off the fire spirits) also seem like outstanding results for skill uses in a Skill Challenge.
I'm betting you run some Reeeeeaaaaally Cooooooool Skill Challenges!
(P.S.: using half experience for a double than normal amount sounds cool, but I'd use normal XP for a smaller amount - I don't see why it would always have to be a larger than normal horde...)
(P.P.S.: I'd have XP'd you for the idea, but too much in 24 blah, blah, blah... I'll have to hit you up later.)
