Should you abandon the straight bar deadlift altogether?
It depends on the goal. If you're concerned about the risk of lower back injury, the trap bar is definitely the safer choice. However, if you're trying to achieve maximum back extensor and hamstring recruitment, then the straight bar is the better option.
Keep in mind that the hamstring's primary role will always be to bend your knee and extend your hip when you're bent forward. While this does occur during the trap bar deadlift, it's to a lesser degree than during the straight bar version, which keeps most of the load on the hip joint, rather than the knee and ankle joints.