Denethor seems to have been thoroughly discussed while I was still in bed! LOL
RE: Denethor... We have both missed that. I have been away too.
For what it is worth... I think Tolkien had Denethor self-destruct so that the reader would be able to celebrate Aragorn's return without grieving for a righteous, unfairly unseated Steward... Faramir would have made a good Steward, but he became an ally of Aragorn's.