I agree with the second of these paragraphs. But I've never had the sort of experience you describe in the first of these paragraphs.
That's the thing. Some players just don't respond correctly to giving them a scenario and letting them do what they want. Letting them do what they want will inevitably degrade into an attempt to take over the city and kill the city guard ending in their own deaths....or it'll end with them not wanting to leave the tavern because no one has offered them enough riches to buy a +5 sword at first level to go on a mission.
Like the group of Rifts players that literally fled the DIMENSION to get away from the plot hook so they could open their own bar and run Gladiatorial matches.
What you describe doesn't strike me primarily as CaW vs CaS, as opposed to a big mismatch between player and GM expectations for the game.
It's related because, if I've gotten this from the OP, CaW is characterized by setting up a scenario and then leaving it to the PCs to solve it any way they want.
So, you say "The opposing army has 1000 soldiers, 200 of them are camped to the north, 200 to the east, and 600 to the south. How do you beat their army?" The answer from some players is "It can't be done. There's too many of them. I can fight maybe 5 at a time." Others say "Alright, we can do this, we sneak in invisibly and poison their water supply."
It is ALSO related to expectations because some players have an expectation that things either work in a CaW or CaS way. In the above scenario, the group that expects it to work in a CaS way might hire an army to make a distraction while they sneak around and attack the commander, figuring that the DM will arrange it so they have a fair fight against just the commander and an appropriate amount of body guards.
But if the DM runs the game in a different way than his players expect, you run into these issues.
For instance, if the DM arranged to have a spellcaster around who can see invisible and spots the party then has a battle against appropriate odds with just the 5 people on watch might really annoy a group expecting to succeed on their cool idea and kill off the opposing army without a fight.
A group of people expecting CaS play who hired the army to lure away the army expecting an appropriate fight and instead finding half the army in reserve who kill all the PCs without much of a fight can be equally annoyed.
After all, the social contract involved in CaS play is that when combat does happens, it happens against appropriate forces that have a roughly equal(always slanted towards the PCs) chance of winning and tactics will influence the results.