I too can't see how the NRL could be made culpable for this. They govern the game and the exact act that McKinnon was a victim of, a spear tackle, has been illegal since the inception of the game. I'm no legal expert but to me it is akin to suing the government because someone was speeding and ran you over i.e. blaming the governors of the law for someone breaking the law. If the act wasn't against the rules of the game then he may have a point.
McLean is probably an easier target. I don't think anyone can say it wasn't negligent at best so he probably has a fair chance there.
It doesn't sit at all well with me that he was happy to take millions of dollars of charity including rehabilitation costs and a life job and then turn around and sue everyone he can. Having a partner in the social work sector, I can tell you there are many people, including lower grade footballers who have suffered similar injuries and have not gotten anything from anyone and live very undignified lives in shared housing. I really do feel sorry for the bloke and I am sure I will have my detractors for what I have said but it feels like double dipping to me.