We would use Trello if they added two things:
1) simple way to delete a card, list, or board (not this archive nonsense)
2) multiple lists in a column
1) simple way to delete a card, list, or board (not this archive nonsense)
2) multiple lists in a column
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!
Is it really different enough that it crosses the threshold of being worth using?
I find that hard to imagine. How much time do you spend looking at archived boards? What would you do with two lists in a column that you can't do today with one list that has some "subtitle" cards?
I'm asking because I'm genuinely curious to know use cases like that, not rhetorically.
My own problem with Trello (that I use a lot despite that problem) is that I feel the need for more than one view of my data, i.e. sorting it in more than one dimension. Perhaps having the ability to have two boards with the same cards. Unfortunately, I cannot imagine any good UI for this.
It's s minor gripe though, Trello is pretty great.