The Cap is just one issue and people seem to be getting side tracked by it.
Closing the pension scheme to new entrants is
THE BIG ISSUE. Close the scheme and it will wither and die.
Having said that, if the proposal goes ahead, then I personally don't consider what we will have left as a
Defined Benefit Scheme, as the percentage of final salary will depend on the outcome of every pay rise for the next 15 years. Every fraction of % pay rise above RPI+0.5% will further degrade the ratio of the scheme. People with a lot of years to go will quite possibly find themselves retiring on 50% final salary
or less 
That leaves a lot to chance and isn't a very solid definition, as far as I am concerned.