Shanata says:
I have never had a group that didn't dissolve before we met the BBEG, I am stoked!
Strahd is not your regular BBEG. Players should not treat a campaign of ECR as "there's a vampire in a castle, let's go kill it". Strahd is centuries old and has the cunning which comes with such a long existence. The castle is his home and he knows it well.
Expect a classic gothic horror adventure: you will probably end up facing Strahd several times, but you will only defeat him once, he knows his weaknesses very well and has planned contingencies to cover for those. It is not entirely impossible that fleeing might be the better part of valor in some parts in this adventure...