Wing EW is essentially an auto win suit on an open map as long as you or your team don't derp too hard. (Colony City and Desert comes to mind)
For rocks, best option is to be sneaky and slap it's back when its not noticing. Scissors, poke shoot contest (he's got limited ammo, so you can approach him more while he reloads). Papers, out range him? (kinda hard). Or try what Acreon said and push him into your team (hopefully not a team of rocks).
As a player that owns a Wing EW, I understand where all the rage and sadness comes from. It's just ridiculous in terms of firepower e..e
Game Count: 3200 Win Percentage: 65.81% Ranking: #15