I must say, I disagree with the concept. But it can be possible, that we speak about the same, but look it with different "glasses".
1., I don't think it is a good idea to put something in a scenario, which is definitely not accessible. I had since playing the PC one scenario of this: the 3rd scn of the Slovak campaign (with the many bunkers with guns...). The Lake Balaton was also impossible to make a DV with Rommel and with the short campaign, but I can imagine, if you try it 50x (I mean the whole campaing

)and have extra luck, you can make it.
2., I prefer the scenarios, where you have to try again and again, maybe even 10 times, memorise the positions and possible moves of the enemy, and have luck (also with the weather) to make the DV. I encountered this situation at least 60%, while playing/testing the Italian Campaign 2.0 and hell yes: it was very hard and I was many times very angry. But, when I made the DV, I was very happy. No more frustration.

But if you setup the scn so, that it is absolutely gives no chance to make a DV, that will give frustration.
I think, it depends entirely on difficulty and scenario design.
I would suggest that you play/test the given scns on the hardest difficulties (Rommel, Mannstein) and if you encounter such situations ("have to try again and again..."), you are on the right path. But if you don't want a certain campaign-path/event acessible, than don't put it in the campaign. A campaign-path, where only 5% of the players will be able to go, has anyway no purpose.
bebro wrote:What would people think of these? To be more specific, I plan to make some scenarios for a campaign that are not designed to let the player achieve a DV.
It could always be that there are some geniuses which beat everything in five turns with a Pak36 and half a Stuka

, but those aside, would people it find overly annoying if they have not much of a chance to get a DV in *every* scn of a campaign?
MV would be possible, and those "unwinnables" would have to be set up so that they are make it still possible to progress with the campaign overall.
Thoughts?