I dont understand one thing , if pilot can eject , why not people ? Also I have heard that the co-pilot wanted to crash the plane making it an Intentional Plane Crash
On a passenger plane no one can eject. Everybody goes where the plane goes. Splitting the plane to ejectable cabin sections would be useful indeed, but I'm not sure how effective that would be as 80% of the accidents are used to happen during the take-off or landing (low altitude but high speed) what isn't ideal for such a solution.
Then I think huge parachutes can be a good option to lower the speed. Or there can be a big fan underneath the plane like those having stability like helicopters.