Should every MySQL table have an auto-incremented prim
I am a huge fan of surrogate keys. I have yet to see a scenario where I would prefer not use one.
I would say Yes.
Read up on this answer Surrogate vs. natural/business keys
Edit
I will change my answer to include the following:
There are certain scenarios that I now use the actual value as a surrogate key:
DimDate (20151031, 20151101, 20151102....)
DimZipCode (10001, 10002, 10003...)
Everything else gets Surrogate Keys.