Pulse the blue LED when recording

Optional setting - just like the power led of a MacBook Pro - obviously this does nothing for functionality other than to let you know something is currently recording, but it would look really cool.

@Mick - It could look really cool. Or be really annoying, depending on where you have your Tablo positioned  :))

How about a slider control to vary the brightness of the LED, instead of just on or off?

@jmichell - Not sure if that’s a possibility but a good option. 

I recall that the Windows Home Server made by Acer had software-dimmable LEDs. It was an Acer Aspire H340 box. I still have one on a back shelf, no longer in use.
If you’re interested, see this link for the appropriate page in the H340’s user manual. The LEDs must have been both red and blue, because they could glow red, blue or purple.