
As an example, I'd like to be able to tell belt1 to be facing left if input=coal, right if input=iron ore, or down if neither if those are true. Items that travel downwards from belt1 would come to belt2, which can be given it's own set of filters.
This would be very similar to "Belt Sorter", but would rotate the affected belt without destroying or creating new items. It would also not actively sort items for you, so it would not work properly if there were two or more items on the belt at the same time. I actually would prefer this limitation, as belt sorter feels a little too 'cheaty' to me.
Ideally it would function as if you were hovering over the belt and tapping 'R' to rotate the belt yourself.