I love my stub nibs! I've had the Nemosine 0.6mm, 0.8mm, a couple of TWSBIs 1.1mm (Mini and Eco) and I ground down the 0.6mm stub on the Nemosine into an italic, liked it so much I did it to the 1.1 stub on the Mini.
Reckless? Sheer madness! Absolutely.
I used a 1000 grit diamond stone I have for my woodworking tools, some fine sand paper, and finally the Revell 12000 pad--which no fountain pen owner should be without.
The Nemosine: whatever the harder bit at the end was? well, it's gone. I like the nib a lot. It's razor thin but wide. I have to occasionally polish it up a bit with the Revell pad because it can become scratchy and you can cut paper with it if you try. I've sharpened and shaped a lot of tools and I've got a few Nemosines around, but still it was a bit reckless. In the end it wasn't that hard to do and it seems to work great. (I've got hundreds of pages of A4 to prove it).
The Mini was another leap into the dark, but I like how it came out too.
And then I bought an Eco with a 1.1mm stub to grind it too....but I liked the stub so much I've just kept it.
My handwriting is pretty bad (though my girlfriend says it's actually pretty good.) I first tried getting finer and finer nibs...but the stubs and the italics actually helped a lot more.
One thing I think I can say from my experience, is that many of us will seek line variation by getting a flex nib. Unless you intend to slow waaayyy down, you won't get much line variation but that springy nib is a lot of fun. Real line variation while writing normally will come from a stub nib or an italic. That's my experience; if anyone disagrees... well, they're probably right.