I wouldn't worry too much about Skill Speed. From the numbers I've seen by people much smarter than me, the impact of this stat is considerably less that the impact of other stats like Crit Rate and Acc. Personally, I would go for Crit Rate before Acc if all you're noticing is some missed DoT attacks. The damage you are missing out on from a single missed Poison is easily made up for by increased chances of Crits.

Hope this suggestion is helpful.