Basically enchants and stats don't matter at all with the new PvP system introduced in legion. Everyone is given a pre-designed PvP template upon entering a battleground or arena. This new template calculates your stats based on your item level. As mentioned by Hashbrowns, the one thing that does matter significantly, is your weapon speed as a melee character (although I believe ferals are of a different case).
So basically, you should try to get the highest ilvl armor and the slowest weapon possibly obtainable by your class, while not comprimising for your main armor type (i.e. warriors need to wear plate armor). The reason for this, is because it triggers an extra 5% stat bonus for wearing your appropriate armor type.
So the reason you see people use items such as "Problem Solving Pendant" and "The Rock" etc. is to increase their ilvl as much as possible. And since stats don't matter, because your stats are now calculated from ilvl anyways, they are the best option.
