Yep, it was fun when a pen leaked in your shirt pocket, wasn't it? The best of it was...almost nobody would tell you. You'd have to find out when you went to the men's room. I think the worst leak offender was a Wearever pen I bought at the dime store. I still have it, but cartridges haven't been made since about the time Ike and Tricky Dick were in the White House. I know...you can convert it to what they call an "eyedropper" model, but if it leaked with a cartridge, I'd really be hesitant to see what it would do with a whole barrel full of ink. Probably spit at me from across the room like a cobra.
I use a Parker 51 and a Sheaffer "touchdown" that I've had forever, and I have a couple of common Sheaffer models and some Japanese "Preppy" pens (much better in my mind than anything out of China), but as I said what I'm thinking about is re-imagining the design...not of the Parker 51 or the touchdown or the Rapidograph. Something simpler than that, and possibly even using a renewable material for the nib (bamboo for example or rattan or possibly something else).
We'll see what we see.