Quote: "Also, I'd like to be able to change the tread title also after the topic was created."
So someone joining to spam porn can:
1. Post an innocent thread and get it approved.
2. Change the content
3. Change the title
Not wise!
Quote: "If I search something and click on one of the results, then go back it can't display the page anymore and I have to start the search over. I'd like this to be fixed..."
There's nothing to fix. It works like any other form - you posted data, the browser is warning you that the data has now expired, may be irrelevant and could corrupt the process. To fix that you would need to change the standards for web browsers.