I personally as a feral druid have hardly any trouble with this. I always make sure my bleeds stay up on a rogue, so when he vanish's i just have to wait 3 seconds for him to come out again, i go bear form just in case he re-opens fast. Another thing i do is i keep FFF on the rogue, so they have to pop cloak before they can vanish, which leaves them open to roots later on.