As far as traits that affect overall developer productivity typing is almost certainly not at the top of the list, and maybe not even in the top 5. However, it is important. If you introduce a degree of inefficiency and friction into communication, coding, documentation, etc. that'll obviously impact overall developer effectiveness.

Consider this thought experiment. Instead of a regular keyboard a developer uses a thumb-based keyboard for everything, perhaps a wired 360 controller with a chatpad attachment. Are they going to get fired over it? Maybe not. Are they going to be less productive than if they were properly touch typing with a regular keyboard? Probably so.