Brasas: Popup warning instead of locking.
"Hej, did you notice you're replying to a (older than x) thread?"
I don't want pop ups but perhaps some kind of alcohol-lock.
I think that old threads need love too. I just wonder how people even find those. Searching I guess but it's pretty random. It is pretty weird to resurrect a thread that who's OP hasn't been seen in ages though.
Edit: I wonder if everything ever written is stored or is there a limit somewhere, there must be.