Thanks @DustinWStout for starting and pushing this subject.
I've been developing a project that relies on this API for most of the year, and am frustrated, dismayed to catch up on the latest developments and am weighing in here.
Sorry, but I have comment that allot of the twitter responses here and the 'hard decisions' blog post itself wreaks of a bad case of corporate myopia.
1) "Rebuilding has its own costs, and would delay our work on other, more impactful offerings for our developer community."
Are you really confident you have something more impactful up your sleeve after getting this much negative response to this decision?
2) "It doesn’t count replies, quote Tweets, variants of your URLs, nor does it reflect the fact that some people Tweeting these URLs might have many more followers than others."
This does NOT negate the share count as at least basic gauge of share metrics (especially for marketers operating on your platform); while they've also pointed out that they've been sitting on their hands for years not achieving anything listed (again, for the marketers operating on your platform).
3) You are discontinuing an API that is relied upon, without a replacement, for the sake of new fancy hipster designed buttons, and your shareholders. That'd be transparency.
A quote from Bill Roth from another blog post about this topic which is pretty poignant: “It’s about becoming the real time media platform of the 21st century, not giving 7 billion people each equal voice just for the sake of it.”