No, YOU aren't listening to Bioware. They aren't going to touch defense until they've controlled for DPS output. Bioware can't properly gauge how effective Merc defenses are until after they've taken their DPS out of the equation.
Sorc/Sage DPS in operations is fine. If you're not getting invited to Ops as a Sorc/Sage DPS, find a better guild.
Mercs are not getting a 20-30% nerf to DPS. Stop making up numbers.