Today I saw a new chip: The IS31FL3733. It is a 192 Led matrix driver. So far it looks like designed for 192:LED. The big improvement over the microcontroller would be: Some real current limiting, which would end up in more consistent brightness; not programming needed (i2c interface to main/host controller); simpler circuit maybe. And you could control more than one 192:LED-module over the same i2c Bus.

I am thinking of changing the PCB design to fit with this driver IC.