Keep in mind that these kinds of features were likely in development prior to the letter, although it's likely the letter accelerated the time table a bit.
If it got GitHub to roll things out faster, then good job to the letter writers and good job to GitHub!
FWIW, I sent an email to Jono Bacon soon after that letter hit HN, and he was very polite and actually listened to my ramblings. I couldn't be more impressed.
The previous stuff they've launched was clearly in development earlier, but canned responses is a fairly simple, high-visibility feature that easily could have been built in response to the open letter.
Yeah. Before that I was really wondering what the heck they were doing with that $100M they raised. I mean, I get that GitHub Enterprise is a good moneymaker, but still.