Remember that the "A" in your equation is the crosssection area of the fluid, which may not be the same as the crosssection of the pipe. Clearly the fluid picks up kinetic energy as it descends down the incline, so v2 > v1. Which means A2 < A1. Hence if the fluid entering the pipe completely fills the crossssection of the pipe, then when it exits the fluid's crosssectional area is less than the area of the pipe. Bottom line: yes, use Bernoulli.
