Here's my system log.

12/15/15 4:53:48.034 PM ipcserver[415]: Valve Steam ipcserver started: 1.04
12/15/15 4:53:48.222 PM com.apple.launchd.peruser.501[136]: (com.valvesoftware.steamclean) Throttling respawn: Will start in 60 seconds
12/15/15 4:53:48.000 PM kernel[0]: com.valve.steaminput ...

Has any progress been made on this?
I'm running on a Macbook, and am getting the same crash.
I dug into the system logs and found some interesting info, but I'm at work now so I'll have to post it when I get home.