I think that's kind of the point, isn't it; that the adventure fights back and does its best to prevent you from finishing it?
Huh, no. This is not a question of conflict between the DM and the players, or the Adventure and the players. It's an adventure that is supposed to make the players happy to have fun with it.
Again, that's the point. Strahd ain't there to be nice and invite the PCs in for a nice sup of tea; he's defending his home against invaders and using whatever he can bring to bear to do so. And if one batch of his minions can't kill you they can still weaken you, to make the job easier for the next batch of minions; and if the PCs aren't wise enough to retreat to town for reinforcements and recovery that's on them. (I6 is one of the very few old-school modules I don't own and haven't read so I'll confess to not knowing whether that module traps the PCs in Strahd's realm or not)
I have nothing against the principles, it's the means employed which are not fun. Invalidating hours of gameplay ? Making the completion of the adventure absolutely impossible ? Not fun.
It's war, not sport, and there's going to be casualties. Survival is priority one.
Even when playing old school, we recognised that the fun was elsewhere than in putting the PCs against impossible odds. I defy anyone to survive I6 if the monsters are played intelligently, using regular even 7th level AD&D characters.
It's only a bad mechanic if you expect adventures to be sporting, without lasting or expensive consequences.
It depends what kind of consequences.
You're assuming there's not already that much level variance within the party to begin with.
AD&D adventures were within a few levels for participating characters, for example, Ravenloft is 5th-7th.
In 1e it's common to have a fairly wide level variance within a party. Experience has taught me that if you take the party's average level, anything within a + or - 2 range from that is usually viable; except at low levels it's + or - half the average instead.
No, for me that is way too much. It would mean for example mixing 1st and 5th level, or 5th and 9th level, way too much for me.
So, if the party average is 6th the viable range is about 4th-8th; if the party average is 3rd then 2nd-4th is viable; if the average is 9th then 7th-11th works fine, and so on.
The level ranges were usually smaller than this, I'd say 3 level on average. The A series is 4-7. G1-3 is 8-12 but it's because there are 3 adventures, so G1 is 8-10, etc. The I series has a 2 level variance on average, etc.
The thing is that, in AD&D, a 5th level MU had more XPs than a 7th level rogue although he was about the same level of power...
Yes. One of them is typing this right now.
Good for you, but as you can see, this does not make a significant percentage of the gaming community.
