This is a very annoying and time consuming problem and I'm sure not something I'd encounter in FCP X if I cared to buy it. Also not a problem in CS6 and it's version of Media Encoder.
I have a project that is composed of literally hundreds of sequences. The only way I know to batch encode these sequences is to drag them from the Premiere bin interface directly into the AME Queue interface. Now in CS6 the first file would take some time to load over into Media Encoder, but each file after that would load almost instantly. So for a batch of 50 sequences it would take 30 seconds for the first sequence and then probably less than 5 seconds for the next 49 to load.
Now in CC it takes 45 seconds for the first sequence to load and then an additional 45 second and up for each additional sequence. THIS IS CRAZY!!!! The first 15 sequences have loaded as I write this and it has taken 8 minutes. It's beyond what one would expect from a professional application. Now maybe I'm doing something wrong but the exact same procedure with the exact same media on the exact same computer in CS6 would load everything in under a minute.
What the heck Adobe? This does NOT help me at work. At all.
30 minutes to load 50 sequences that are each under 30 seconds in length.