Reforming the Watchtower would be like gilding a turd. It would look better on the outside, but it would still be a turd.
Anyway - this reform talk reminded me of a link I stumbled upon in my Favorites: http://www.prweb.com/releases/2007/8/prweb546361.htm It says "a reform group", but it seems like a totally separate group to me.
As for the letter we're talking about, it may perhaps make a few people think about things, and sow a few doubts, which may in the end lead them to get out. True reform would have to come from the top.
I'm a little worried that when witnesses start receiving the letter, they may do a simple Google search for a portion of the text, and find that it originates from 'apostate' sites like this one, and that'll be enough to convince them to bin it; probably burn it, knowing them.
But again - it may help a few of them, so I think it's worth it.