I've seen every episode except the one just recently aired.
My take on it is if you watch the first and last episodes of S1-3, you could probably get a pretty good gist of the main conflicts of the show and where the characters stand. So essentially I think 6 episodes could get most people caught up to S4.
Another thing that might help is that Kurt Sutter intentionally creates a "split" for every gang. There are purist Aryans, then there are greedy lost their way uber evil Aryans that are ok to kill. There are purist Mexicans in gangs, then there are rogue, will do anything, mercenary Mexicans in gangs that are ok to kill. There are hard core ruthless black gangs, but there is the loyal hard working solid black gang that supports the SOA. There's the cop who won't let his "friends down",and then there's the uber evil merciless one dimensional ATF agent who is ok to kill.
Sutter has a wife and two kids at home in real life. He shows the SOA killing "classic" old school Aryans, how does he know they won't stab his children's eyes out with an icepick?
IMHO this is part of why the show is very uneven. Every rogue element has a "pure" version which is treated with kid gloves, and a *******ized version which even purists of the originals would hate, and thus are ok to kill or be the main antagonists on TV. I kind of see it like that strange Jennifer Lopez movie Enough, where she marries a guy who beats her, she leaves him, trains to kill him, even though he's set up as a one dimensional bully, then at the end, she doesn't kill him in cold blood, instead there is some deus ex machina to show she had no choice and it was just self defense and bad luck for the other guy, so she can get the satisfaction for the "kill" but carry none of the guilt or pain from being a "bad guy" herself. To me, this is quintessential Sons of Anarchy. Clay is bad, bad, and bad. But Jax is good, good and good. And the writing will only follow that mantra no matter how far off the rails the writing has to go to get it done.
In my book, Kurt Sutter has pretty much no choice at this point. The show must carry certain gang/MC worship and fandom/groupie type behavior within it, not just the SOA type gangs, but all the other gangs too. He makes a storyline that pisses anyone off too much, sends the wrong message in their eyes, and my guess is Sutter's children die. Why would a bunch of criminals kill someone's kids over a TV show plotline? I don't know, why does Kevin Smith need bodyguards while making the movie Dogma? There is a reason no one really wants to or has made many movies or TV productions about organized gangs before. I've read Sutters blog before and he openly admits he has anxiety issues and takes medication. I really don't think he understands at it's core. logically, why the Emmy voters will refuse to vote for a show where organized gangs get their wet dream fulfilled in an all out, no holds barred one dimensional cop kill.
This show carries a subject matter that I think no one, I mean no one, could tackle honestly and within three dimensions, unless they were 90 and dying of terminal cancer already and had no family.
I feel sorry for Sutter's children. The only way their dad gets to shift past doing super charged fan fiction is if he's willing to get their throats cut for it.