There is a very real sense in which the terrifying tragedy that we as an audience witness on the stage during this play is something that could be said to cleanse both us and ancient Britain of various violent and tragic emotions. This is of course one of the definitions of a tragedy if we go back to Aristotle and his idea of catharsis. He argued that we must undergo a kind of purging whilst watching tragedies so that we are able to leave the theatre having had a chance to express various emotions such as sadness and anger and rage by watching them played for us on the stage. Spiritual regeneration in terms of catharsis is definitely something that can be identified.
In the same way, the ending of the play points towards the future, and there is definitely a sense that the new rulers of Lear's kingdom will definitely incorporate what they have learned from the play into their lives and that of the ancient kingdom. Consider how Albany ends the play:
The "young" characters that he refers to have definitely seen plenty of things that will make them wiser rulers. They, as the next generation who will rule ancient Britain will be able to learn the lessons from those that came before them and usher in a time of spiritual regeneration that will enable them to do a better job than Lear and his daughters.