I think its a fine line to succeeding or failing most skill checks if the DM constantly call for skill checks. I tend have players automatically pass most but only call for checks when its critical. In a social type setting roleplaying always trumps skill checks but if a player is vague or abstract in describing their action Ill make them roll one.
I'm not sure what this has to do with monster mechanics, but I agree with your comment.
One thing I learned from the (clunky) 4e skill challenge rules. If you ask for too many dice rolls, you guarantee failure. The GM should be aware of the right number of checks that should be required for skill-based challenges. And especially for scenes that are narratively freeform - like the PCs pulling off a heist, say - the GM shouldn't require a check for every task, but rather have maybe 7 checks that represent broad narratively thematic efforts (e.g., scout the area, get everyone good disguises, distract the VIP, sneak the rest of the team in, overcome the magical security, sneak out, lay a false set of breadcrumbs so the villain doesn't know it was you). And failed checks should lead to complications that can be overcome, rather than a totally failed heist.
I suppose there could likewise be guidelines for combat skill challenges, with examples to encourage the GM to include them in scenes. Like, if you throw a slightly too-powerful foe at the party, you could include some element in the area that makes defeating that enemy easier, but which requires some skill checks. There'd be guidelines for how many checks, what DC, and what sort of benefit it should earn the party.
For a simple example, you might fight a giant fireball- spitting newt that climbs up stone spires, letting it act like artillery. But a PC could shove a spire and cause it to tip over, dealing falling damage to (and possibly pinning) the newt.
For a complex example, maybe your low level party with no magic weapons faces a ghost in an alchemist laboratory, and an Arcana check determines that there's the right reagants here to create a burst of positive energy that will make the ghost lose its damage resistance. But to get the reagants you need a Perception check to spot them among the shelves, an Athletics check to retrieve them from a high shelf, and then a Religion check to calibrate the right mix to affect this particular sort of ghost.
