I've MST'd my own 'fic before and am in the process of PPCing another, and as others have told you, hS has sporked his own 'fic, as well. I'm sure there are plenty of other examples.

In other words: go for it!

As has been said, hS has sporked his own fic, and I'm aware that a couple of other PPCers have done the same, though I can't recall their names at the moment.

Besides, it shows you're willing to acknowledge that you've written bad stuff in the past and are willing to improve. If I had any of my old fics still hanging around, I'd do the same. Go for it. :D

I know Huinesoron - or someone he's hosting on his site; I sometimes have trouble keeping agents and handlers straight - has done at least one mission of his own fic.