It's not a bad idea, but there are other features for a new translator application higher on my wish list.
Being able to translate collaboratively isn't something I really miss. We already sort of have a tool for this; Messenger. It lets us discuss translations to the extent we need.
Zipping the finished file and sending it to Patchou is even less of an issue.
The single biggest issue when translating is trying to figure out just exactly where the text appears in Plus!, and how much space is available on the current line. Therefore, I would like a tool like Choli's that also displayed the actual Plus! window next to the text translation fields, so you could always tell on-the-fly how much space was left.
I realize that this probably ain't doable by anyone except Patchou himself, and I'm sure he has better things to do.
/ 
