There is a lot of talk about "paying one's dues" but lets face it, it makes for a hostile community and most gamers these days are not going to have the patience to deal with it when so many games remove these kinds of barriers that prevent you from just jumping in and having fun...
...Because Sins requires so much dedication to play and enjoy online, it makes the online community smaller, which just makes it increasingly unfriendly for new people to try and get into. Thus you have a small dedicated "hardcore" community, and some people who just like to play with their friends via ICO or LAN.
To date; SoSE has reached a HUGE customer base that has "aged in place" so to speak, with it's "hardcore" MP community being at the forefront of testing balance, bugs, and brainstorming. As a result, much brain damage has been had, and pardon the poetic license here, but the greatest contributors amongst us, good and bad, will be found in MP games, and of this there is no valid argument to the contrary.
"New blood" will always be an illusive carrot on the stick, but at what cost to the "community" as a whole? Rebellion as the OP suggests has issues, but not unlike any effort that is essentially a progressive pursuit of perfection. We don't need histrionics here, what we need is veteran players that embrace new players with tolerance, patience and a certain je ne sais quoi in nurturing them towards the accepted societal standards adopted by the aforementioned "community". 93.4% of virtually all "issues", of every every kind, could be remedied via expressed adherence to these standards. I would much rather participate with the dysfunctional contingent as-is currently to get what I need out of SoSE Rebellion, than put in the effort of subscribing to a higher ideal of player-base ethics. Those of us that abide in the MP community do so with all it's faults and blemishes because it's a labor of love for us. We pretty much know all of the ugly sides of the game, but we love it nonetheless. There is no thing like it. HOWEVER, to share this love of the game, and that's really what this is all about, a bare minimum assent of essential edicts must be made resolute.
Because...
There's a troll under every bridge - the only way past is to not let them get in your head. I contend that Trollism is the single most corrosive thread in our midst. Setting an example of Zero Troll Tolerance will go a long way towards not letting new players succumb to, or indeed become one. Because, remember: trolling for trolling sakes is a way of life. You can do it in your sleep (it comes so natural to some). You see it in MP games, on the boards, you can see it at the grocery store for that matter, but beyond cohering around sound principles and fostering an attitude of inclusion, the SoSE "aging in place" will continue to be fraught with counterproductive experiences, replete with angstful gnashing of teeth. We must all be emissaries against Trollism in the campaign to maintain, and retain.
In closing...
SoSE does require dedication to play and enjoy - "...jumping in and having fun." I'm afraid is never going to be one of the defining characteristics of the game. Alas, such is the lament of those that want something worthwhile - it comes at a price, but it's really not that complicated - it's quite simple really. You want to enjoy something you're apt to pursue, you have to take a part in it, (if that's what you want to "jump into"). Critical thinking in the input/feedback sense is crucial to furthering SoSE, but being a bystander, no matter your area of interest, be it in SP, MP, Modding, or even trolling - ridicule and complaints bears no merit.
Standards; Promote and Publicize, Embrace and Enforce.