I agree with not having bright, especially blue, LEDs. The only use I would consider blue for would be to alarm me of low battery power because it draws attention. But red is far more common for that purpose.
Green ones can easily be too bright like I found out after buying a Razor mouse. I don't need extra lights to walk about in my room or interact with objects on my desktop (the physical one) when that rodent is plugged in.
Yellow, orange/amber, red and soft green, I'm fine with those. Though I see it gets complicated because of the LEDs sitting together so closely and interfering with each other.
Is there a possibility to dim LEDs? I guess you would need some extra thingy on the board to do that?