Generaly I've always found mosaic datasets as a great way for working with LiDAR data. Recently, NOAA NGS has released new topobathymetric LiDAR for the Atlantic coast. Because the submerged topography has been coded to class 26, it is impossible to use mosaic datasets with the goal of creating a topobathy DEM (where 2 - ground & 26 - submerged topography are simultaneously shown).
When adding rasters (LAS) to a mosaic dataset, the user can then specify which Class Types to be shown in the mosaic via the Raster Type Properties dialog box. Currently, only the generic ASPRS classifications are shown, values 0-18. If a vendor classifies their LiDAR outside of this generic range, a mosaic dataset is no longer an option. Because the NOAA NGS topobathy LiDAR has submerged topography classifed as 26, mosaic datasets are not functional for these data. It is possible to use LAS Dataset to Raster as a workaround, but this may not be ideal in some situations.
I propose adding an option to the Raster Type Properties dialog box (within mosaic dataset Add Raster) that would allow users to type in and specify their own class types. I think this would appeal to anyone using topobathy LiDAR as it would increase the degree of user control over the tool.