There are so many things I would do differently if I were to rig this over again. I learned a ton from just this one rig, and I think a lot of what I learned will be transfered over to my future rigs.
Edit: Completed Rig:
Real nice progress, you’ve come a long way in a short amount of time. I like the rigging on the chains and beard- a good combination of automation and manual animator-control.
I guess from this point you’ve probably got two natural routes of progression- you could focus on advanced deformation with muscle rigs / face rigs etc, or you could focus on the more technical and scripty stuff (getting a basic autoRig working or writing some tools to help you in future projects). I guess doing both would probably be a good choice!
Looks nice! I think you should give the rig to some animators and let them do what they do best: break stuff! In the end it is they who are going to use it and you learn a lot. 
Thanks guys for the response! I’m finishing out the last couple months of school and I’ve been mostly focused on python development. I’ve completely switched over to Linux for everything. It’s starting to get a bit overwhelming, but I’m going to keep pressing on.