Ehhh. I suppose it wouldn't be a bad idea as long as users can see when their own posts are deleted, although quite often when users delete their own posts they prefer to leave a reason why for other members or for staff to read. I don't think it's enough of an issue to bother hiding deleted posts, especially when I think that users absolutely must be able to (not even that - have to imo) see when their own posts are deleted and I don't know how easy it'd be to make a plugin which shows only that. If it's not much effort then sure, but otherwise I don't think it's important enough.
The distinction between deleted posts and deleted threads, by the way, is that threads are very rarely deleted and when they are, it's normally because it's an adbot or a totally unacceptable thread for one reason or another. Posts are a lot less serious.