I agree with leaving tutorials unlocked forever because they could be followed for long periods of time and if somebody has a question they can still ask it in that thread rather than asking in a new thread. For other topics, perhaps a 'Request Unlock' button could be added that only the op of the thread can use. The new lock times seem good.
Every topic has a "Report to moderator" button on it. Simply click that button and say that you would like the topic to be unlocked and a staff member will unlock it for you momentarily

Well, I think that OPs should have an option to unlock their topics since they are already to lock them.
I can't easily add this feature because giving users permission to unlock their own topics would mean they could even unlock them if a site moderator purposely locked the topic. Adding in custom permissions just for auto-locking is too much work right now. Use the moderator report button, it works fine.