This is a easy suggestion..
When nameing you thread some times we tend to miss spell a word or just make a stupid error or decide to change the name at the last second.. but after hitting post we are unable too..
The feature i ask for is when changeing the first post of the threads subject field it should changes the whole threads subject and not just the field of the post itself..
I accidently wrote "Imagie size" instead of "Image Size" and when i changed the subject my post says "Image Size" but the thread itself is called "Imagie Size" still...
Just a simple suggestion that could be helpfull if someone makes a error or finds a better name for a thread.