wel, a few reasons. A: there was no new album to make one with (well, unless u count the 8 MA songs). and B: sales are not too hot with remix albums. theyve been going downhill, so i wouldnt be suprised if they stopped the ayu-mi-x series altogether.
i myself am waiting for an ayutrance or ayuro. wouldnt be suprised if they never came though. o poo.