resil is very important because it severely curbs incoming burst damage. on targets with little-or-no resilience i can crit up to 3000 damage with mortal strike on a clothy with enrage up. conversely, that same class with resilience has a much lower chance of getting crit as well as reduces a big hunk of my crit damage should they be crit.
in other words, im echoing what teddy said; dont drop a pvp or arena piece for it. altho ill add the corollary "unless you already have more than 350ish resil and 10k unbuffed hp". haste is great, but the only things ive seen with haste that work in pvp are haste trinkets (abacus of violent odds etc.) and weapons (drakefist hammer etc.), and the weapons only count if you cant get better from arena (and if you can, you should).