Sorry I missed this until now :x Life Orb, as well as the SpA and Speed investments are somewhat mandatory to Mixed Druddigon's success, but if you feel upset by Druddigon's current bulk you could always try moving some EVs from Attack to HP to assist this =) Unfortunately, getting worn down is one of Druddigon's biggest issues, and the best way to solve this is to be a little more conservative when playing it (ie.not switching it in recklessly, alternating between switching it in with Lanturn and Rotom-C, etc.).
Tehy: like i get the feeling you're pro or something
Tehy: on this ladder
Tehy: it's so fucking hard to tell