At the time, Breaking Bad had finished with such level of perfection that the sole idea of even trying to continue it was VERY scary, as it is rare that any prequel or sequel has even near the level of their first installment.
Of course, they delivered, they surpassed any expectations. So, now we can trust Gilligan and team on whatever they do. At the time, even with Breaking Bad being so good, it wasn't still clear that they could keep that level.