I go back and forth on this one, but if pressed for an answer I'd say no, not ALL should receive their firearm rights. Anyone convicted of a violent assault, murder or man slaughter, or sexual assault should not. In my opinion they should not be let out of prison, but short of a life, or death, sentence they will be released. Here is where I am seeing a lot of misunderstanding being posted.
I work for the local SO, in the jail. Most people that want to stay out of trouble do so. There are plenty of programs and opportunities out there to assist them in rebuilding and reentering society. In my experience the ones that truly want to stay out of trouble are successful at doing so. But far too often when released they go right back to the same crappy hotel with the same tweeker friends doing the same tweeker crap. Hell, some of them have even bragged to me that the first thing they are going to do when they get out is get high and raise hell with their old friends. I usually respond, "See you in a couple of weeks". Which generally proves to be true. It is a way of life for them, the life they have chosen. They only live to get high, nothing else matters. Not jail, not prison and certainly not death.
Gang members only live to make money, have sex and get high. They only purpose in life is the furtherance of the gang. They are drones that have bought into the popular myth of the gangster as portrayed by the music and film industries. A very, very few live long enough to see that the gang is a lie that has wasted their life. When they are ready they will leave the gang. Heck, the Feds will assist with relocation for their family, tattoo removal and even medical care for those that provide good, high level intel.
So no, I do not believe that ALL felons should regain their firearms rights. Those that are habitual criminals, as defined by law, should never regain their rights. That will not stop them though. Criminals, by nature, do not following the law.