I agree that needing to add your own HTML markup is a pain. However my experience with a number of other forums where a WYSIWY(almost never)G is provided has convinced me that PerlMonks' actually has landed in the right place by placing the smarts on the far side of the keyboard.
For reasons I can't fathom every online editor I've used offering more than trivial markup gets it wrong, especially when trying to handle a mixture of prose and code. Some make it almost impossible to post something and have any idea at all what it's going to look like. Even big players like Google can't get simple editing right.
PerlMonks seems to get scorn poured on it for "looking old". Maybe, but I find it much easier to navigate than any other similar forum I've used - bar none! I use Recently Active Threads as my "home page" and open threads I'm interested in reading in a separate tab. In my opinion the sideways tree view makes the flow of conversation much easier to follow than any other forum I use.
Yes, it would be nice if it were easier for noobs to enter nice posts, but for the most part a poorly formatted post is a great heads up that the OP has applied laziness in the wrong way.
I consider for the most part PerlMonks ain't broke, so please don't "fix it"!