alt Hacker NewsNever have I thought "I want a mouse with modifiable firmware", IMHO this is only going to lead to more bugs arising from the associated increase in complexity and the "we can always fix it later" mentality. All the mouses and keyboards I've used have a mask-programmed MCU, and essentially no bugs to speak of.
I think the point is less to add features and more to lower the barrier to entry for people making mice, since, as you said, in large part keyboards and mice are appliances to the degree that it should rapidly converge to a stable set of features.
Plus, on a human level, I wouldn't be surprised if the teams working on mouse development were annoyed they couldn't show their past work in the same way...