This card is fantastic, and I plan to play 3 in every deck, completely replacing the need for Plascrete Carapace. "What's the point of Steelskin then if it can't save the runner from certain death?" The point is that you very rarely have only 2-3 cards in your hand, especially against Weyland. What's more likely is that you have 5 cards, the corp plays Scorch, and you lose 4 of them. Even if you're only holding one of these, there's an 80% chance that the first Scorch will hit it. You'll go back up to 4 cards, which is conveniently just out of range for the second Scorch. Better yet, they didn't know you had it, so it's harder for them to plan around (unlike Plascrete). A crafty corp can figure out a triple-Scorch if you have a single Plascrete out, but if they don't know for certain that you have some kind of defense, they probably won't.
Honestly, if this card is as good as I predict, we may see more Traffic Accident than I was thinking. An Accident has a 60% chance of dodging a single I've Had Worse, and will put a 5-card hand down to 3 (just in range to Scorch without worrying about the I've Had Worse). But the 2-tag requirement makes it harder to pull off. Either way, it makes the deck weaker, and only works 60% of the time, so I'm super okay with that strategy existing.
Anyway, the main thing this card has over Plascrete (besides the secrecy I mentioned earlier) is that it doesn't become a dead card in non-Weyland matchups. Even against a deck that you're certain doesn't run any net/meat damage cards, this is still a 1 Diesel. If Diesel costed 1, would you still play it? I know I would, especially in-faction. This card is fantastic in Anarch, and I'll probably still be shelling out 6 influence to put it elsewhere.
The last great thing about this card vs Plascrete? If you're uncertain about what your opponent is playing, you can wait to use it, and all it does is take up a spot in your hand. When you're running Plascrete and you find yourself against NBN: Making News, you're never really sure if they shelled out the influence for Scorch. Do you shell out the 3 credits and a click (or 6 credits and two clicks if you want two of them) for your Plascrete, or do you take your chances and not play it? You won't find out the correct answer until it's too late, but 3 credits is a lot of money sometimes, especially early on. It's just another reason I hate playing Plascrete and love about this card.
So, to summarize, this card is better than Plascrete because (1) Your opponent has a harder time playing around it, (2) it can be used as a draw card if you don't need damage prevention and (3) it doesn't cost anything to use as protection. The only things Plascrete has over this is (1) Sometimes that first Scorch will miss it if you're only holding one, (2) it prevents one fewer damage, so if you're only holding 4 cards, they can still get you with 2 Scorches, and (3) it costs 2 influence outside of Anarch.
The decision between the two seems pretty obvious to me.