I completely agree with your first point. Being able to actually delete boards would be great, rather than having 5 archived boards.
I disagree with your second, but am genuinely interested as to why you might want this.
The idea is with Trello and other kanban systems is you move tasks from the left to the right. If your intent was to create another type of transition, you're breaking the underlying concept. If your intent is to break up a single list into multiple small lists for organisation, could you use something like colour coding instead?
edit: have just read further down that they don't intend for it to be a strict Kanban system, so perhaps there's room for multiple lists in a column. I'm still interested in your specific problem though!