Eh... Well, in my opinion, I really don't care if people had the ability to lock a thread, but at the same time, there could be members who would lock their thread to prevent someone from continuing to post there. You know what I mean? Someone you don't want comes along and seems to, you know, kind of ruin the quality of the discussion and distract from the topic. You don't like that, so you decide to lock the thread. Then a week or two later, you want it open again, and you unlock it, and the process goes on and on and doesn't end. I'd assume people would lock the thread for the wrong reason, and lock them on whims.
I'll usually lock a thread someone made if that someone requests it, though. I don't particularly need a good reason for it. The way I see it, it's your thread and if you want it locked, I shouldn't refuse. Unless I ask why and it's something stupid like something I said above.
About renaming threads, I don't at all care if a member can change their thread name or not. I don't really see the whole abuse part of that being logical, though. As long as the thread name is relevant to the topic, then I don't have a problem with you changing the thread name. To me it's just not that big of a deal. :/
