Good poll. It was a hard choice between bullet penetration, cover system, bleeding, and the progression system(Because it was done somewhat real instead of unlocking scopes for sub machine guns, ect.) I went with bullet penetration in the end, with bleeding and progression close behind, in that order.
Edit: Tanking was never bearable in RO for me, except in combined arms. But now im more willing to try it and I probably won't be leaving the server when a pure tanker map comes on now.