I don't understand how the singleton spade makes it any better. Given my singleton spade, I expect that W will correct to 4♠ which partner is likely to double. With hearts breaking (and possible heart ruff in dummy) it wouldn't surprise me if they make it.
In my world pass denies a stiff spade. (I wouldn't even double with small doubleton and a balanced hand). So a simple calculation shows that if you believe them to have 8 spades for the vulnerable 4♠ bid, we will suffer a spade ruff at trick 1.
I like them, it is more difficult for opponents to double you compared to Raptor and the major is immediately known.
Furthermore not being able to make weak jump is not nearly as bad as losing a natural 1NT overcall.