Its a matter of playing on an even ground.
You don't even seem to realise how good some trinket combos can be. Take
Vial of Shadows . Great trinket baseline right? Now, fun part is that the procs scales with AP, combine it with the
Badge of Conquest, wich gives about 4900 AP when you pop it. One trinket just buffed the other by a substantial amount.
Or lets take Human Rogues running with double
Badge of Conquest (one being a lesser version), meaning they have a trinket up for EVERY SINGLE DANCE.
Human Mages with double Mastery trinkets? Enjoy 50k shatters.
No, the human racial won't turn a 1800 player into a gladiator, but yes, the current trinkets are powerfull enough to clearly give an edge to anyone being a Human. Its not worth faction changing, since Horde have almost equally good racials, (Goblin Jump, Silence), but if you're Alliance, you're gimping yourself playing anything else, and those trinkets can make or break a game.
Here's the ladders of the 2 best Battlegroups in the US. Kinda proves my point, take it as you will.
US-Bloodlust Ladders
http://us.battle.net/wow/en/pvp/arena/bloodlust/3v3
US-Nightfall Ladders
http://us.battle.net/wow/en/pvp/arena/nightfall/3v3