rogue, has more lockdown abilities, has 2 guaranteed escapes (vanish and prep) and is OP in high end pve gear. The class is less mobile tho.
druid: balance is shit to gank with, ganking is mostly 1v1 and balance are one of the worst 1v1'ers.
feral has amazing dmg and offheals, you also have a higher chance of chasing down people who run away, which is harder for rogue.
TBH if you want to gank people and make them be like dafuq happened, I'd go rogue, for more diversity go druid.
PvP gear is better than LFR gear, PvE gear only gets better at ~540 ilvl (LFR is 528).