Although, the other questions raised in this thread, about what parts of our workflow are problematic, are worth talking about separately.
Moving from a manual patch-based process to a DVCS where branching is cheap and the workflow can be moved to push/pull would be a huge step in the right direction.
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.
Twisted needs more friends not fewer. Given everyone here has day jobs in addition to contributing to Twisted, getting rid of the patch-hell that is the current review process would help everyone even if Trac is kept for issue tracking.