Thanks for sounding the alarm on this. I am concerned about these aspects of Steemit as well. I worry about what happens if the image hosting service I'm using goes out of business and I have to migrate all the images for my posts to a new service. If I can't edit my really old posts to change the image links, such an event would effectively ruin all my posts. And I value my old posts. I look at my overall blog as a resume of sorts; someone viewing my profile might skim over my list of old posts to see what kind of content I write and decide if I'm worthy of being followed. So being able to always edit posts is quite important, as is being able to see the history of edits which should be easy given the nature of blockchain based storage.

Also, I want to be able to vote on old posts and still get a curation reward for it. The way it is now, I have no particular incentive to vote on posts which are past their initial payment period (other than altruistically wanting to be nice to the authors). It's sad that even the best, most craftily written posts only get a brief 15 minutes of fame before being consigned to the dustbin of blockchain history. Let them live on forever, in the same way that well written books can effectively generate lifetime royalties for their authors!