Twisted has a very polite club-like culture where some are on the inside, most aren't and it's clear where on that line anyone is. Submitting to the pain of the current submission tools almost seems viewed as a kind of worthwhile hazing to weed out the unworthy. A lot of the resistance to change on this issue over the last year has had a lot of that flavor to it. Itamar's logic on why Twisted shouldn't make contributing easier being a prime example.
I did not say contributing shouldn't be easier; I said getting more contributions is pointless (and annoying to contributors!) if we can't manage to get them incorporated into trunk. If DVCS will make code easier to incorporate, by encouraging contributors to iterate on patches, then we should certainly do so. Given the feedback you and others have given that seems at least worth trying.
There are other additional things we should work on though, e.g. giving better feedback to new developers.