It would be cool if heatmap.bin could be restricted to the top N most abundant OTU. Currently it is hard to get much from it when there are thousands of OTU.
Also I think the group labels could be scaled larger. I made an image with 12 groups and converted it to a 700px-wide
png for web display, at which point the group labels became microdots, although there was plenty of room above each group
column to show them.