It only takes two things to shake up the meta. Give BRD/MCH the piercing debuff on Straight Shot and Gauss Round respectively (would say Hot Shot but that's only 1 cast per minute atm and I doubt SE wants it lasting that long), and nerf Trick Attack's Vulnerability Up potency to 5-6%. The emnity changes to Diversion have weakened the value of Shadewalker enough that most groups are fine without it.
Good long term changes would be moving the vul up debuffs given by Contagion/Radiant Shield to Tri-Disaster (replacing Ruination with a 5% Magic/Physical Vul Up or Vul Down debuff, according to what pet you have out) while removing its reset mechanic, and allowing Brotherhood to proc off of spells and apply its bonus to all targets, with its values decreased to reflect that. But these things won't shake up the meta as it is.