No waiting for me; I'm pre-ordering the season pass as soon as it's available for PC. Bethesda has a great record with DLC (minus the horse armor) - especially Fallout (even though New Vegas wasn't exactly Bethesda). They have earned my trust especially since they've stated that the season pass will include all DLC for Fallout 4 ever. My trust in them is theirs to lose and I have no reason to expect F4 will be any different.
Now that said, it's 1) only $30, and 2) I'm incredibly confident that at the very least, I will feel I got my money's worth so I don't view it as a huge risk. There's virtually no possibility that I'll feel 100% of my money was wasted. In fact, I'll assume that they'll have at least two content DLCs that I'll absolutely love. That means I stand to "lose" $10 at most. Not a big deal to me. Now consider that at $20, there's still $20 left of DLC. Even if I enjoy just half of that, it means that I came out even cost-wise.
So, no waiting for me.