I think perhaps mandating that all cricketers wear helmets in club cricket is not a bad idea (I know some will disagree with this). Take the choice out of their hands. I know a long time ago I used to feel they were unnecessary (accompanied by some foolish bravado on my part as well), and that they were a pain in the backside. Getting hit changed that very quickly. Personally I always have a helmet on even when facing spinners. A ball even at 50 miles an hour can hurt or cause damage if it hits some areas of the body let alone at 80 miles or more. Make it sort of like a OH&S regulation perhaps.
In the near future I can see some repercussions. I agree the other posters that the bouncer should not be banned - it is part of the game and has been always. In the old days, there was a gentlemans agreement of sorts in international cricket that quicks did not bowl short at tail enders, as they did not have the ability to deal with them and it could lead to someone getting badly hurt. With all the protection these days, that went out the window since for the most part people felt no serious damage could happen (a few bruises aside or the odd fracture to the fingers, ribs perhaps, all of which would heal and have no long term impacts). For the most part this has been the case.
Even with no outlawing of the bouncer I can see fast bowlers now becoming reluctant to use it in the near future. Seeing quicks like Mitch Johnson having both top end and lower end batsmen hopping about with fear was something of a spectacle that many enjoyed (myself included) without a second thought that perhaps someone (more likely a tailender) might get hurt. Part and parcel of the game. The sight of an express bowler having the opposition running scared has always been one of the greatest contests in cricket and one that got the crowd going. There is something primal about that that has always excited crowds (cricket's equivalent of the roman gladiators in ancient times). More than anything else, facing up to someone quick is not just a test of skill or technique but a test of your will and courage to guts it out. I think that should always remain a part of the game.
However, I think in the near future at least that won't be the case anymore. I think any quick bowler will be at least a little hesitant to use the short ball particularly against lower end batsmen. Crowds may turn on the fast bowler instead of cheering them on now when they do so, which completely changes the dynamics of the game even without any official changes to the rules. I am sure some sort of normalcy will return in due course.
At club cricket, I think like some others have mentioned, umpires should step in an warn the bowler and ban them if it persists. Some people in my view at least seem do seem get a kick out of roughing batsmen up (and I don't mean as part of a strategy to get him out but rather with some intent to hurt), and someone could be hurt seriously. That sort of thing needs to be stopped. Its meant to be a bit of fun on the weekend, but people can certainly take it very seriously at times.
With regards to helmet protection, I think no matter what you do, there is always likely going to be some risk. For example in motor racing, deaths and serious injury still occur, and that is the nature of the beast regardless of how advanced the safety features have become these days. But compared say 20 years ago even the difference is amazing.
Similarly there is always the chance that a 90mph ball sneaks thorough some gap somewhere and causes a serious injury. But I am sure the risks will continue to decline as people look at improving safety further.