I've been monitoring developments in discussion software for years hoping to find a more up to date solution that offers threaded view but it simply doesn't exist.
VBulletin has an 'old' version of their software that allows a 'semi-threaded' solution BUT... it's no longer supported - so all the 'new' stuff wouldn't be possible.
There is a good chance we may be forced to make the move eventually. I ran a poll on this board not that long ago asking which 'view' our members would prefer... the result was overwhelming in favor of fully threaded view like we have now.. BUT - - in comments everyone would like a much better mobile version for phones and some of the new features we don't currently have..... unfortunately no such animal exists and believe me... we've searched.
If anyone knows of a solution we'd love to hear about it. - JamesJM