I am a volunteer for doing Chinese dramas. There are a lots of reasons why a drama may not complete totally. Mainly, as volunteer, it is hard sometime for people to get time to it everyday. We are encourage by Channel Manger (who are mostly volunteers too) to drop a few line each day if possible. In my own experience, I do take times to complete a drama. At times, I am able to finish at least two episodes a week. But then, something in life came up and I had to stop for a few weeks. Sorry to say that, since this isn't a pay job, the priority is low for me.
Of course, there are also volunteers who tried their best as the foreign language isn't their first language. Even though I may be fluent at Chinese. There are many "type" of Chinese slang. Each region of China use words a little different from others region. Similar to English, there is modern English (I, my, me, you) as well as Shakespeare/King James English (thou, thee, etc).
Also, China is a country with rich history. Thus, there are a lots of difficult terms used. It takes a lots of time for us to research. Since not all dramas can come with hardsub, it can be frustrating if one can't figure out the words the actors are saying and then, the volunteers have to give up.
I totally understand your frustration in purchasing a service that not totally meet with your expectation. May I suggest that you contact Viki for this matter. As far as I know, Viki does hire (or at least they advertise for) Chinese translator.
In weeks to come, there will be less dramas to watch on Viki as they will be removing all the Fan Channel. Perhaps, you may want to contact Viki and ask if their hired staffs/translators can help speed up the translation.
As a paid customer, I believe your voice of concern will weight more when contacting Viki directly.
Alternately, you can watch (if you haven't) the following Chinese dramas which are almost 100% translated to English. Can't say that the acting or plot suit your taste. But at least something to watch...
The Legend of the Monster