Adding an option to disable the opacity that allows the album artwork to show through the main deck area would be a nice option. Brightly colored artwork showing through behind the deck interface is often distracting, and makes it difficult to discern the first downbeat marker in the waveform area. Overall the opacity feature make makes the interface washed out.
In general, the 1st Downbeat Maker is often hard to tell apart from the other beat markers. Having the 1st downbeat indicated as a different or brighter/bolder color would be great.