Comparing BRD from 2.x to 3.x in raid content with regards to preferences in raid group is odd. BRD was the most preferred DPS early in first coil for those silences in turn 1 and 2 and they were also good for feeding the adds to Caduceus.
Because of all the jumps and phase changes in second coil, BRDs and SMNs were also preferred DPS. A lot of BLMs switched to SMN for second coil.
Plus, Ballad and Paeon gave the rest of the group more resources when learning fights. They provided more tools to other jobs this time, so that Ballad and Paeon don't have to be deemed necessary.
When groups are dealing with wipes in the last 5%, switching a DPS out for higher DPS output without losing from the change in utility makes a big difference. And with legacy server characters already being 50 in most classes and characters on most servers already 50 in most classes by the time second coil came out, switching your DPS job in your static was simpler.