I only can speak for myself : Pardon me, but before dreaming of a n 6, I'd like to have n 5 running without hickups.

I don't really "need" new features
(but one could imagine nice things like "real" instances, or having multiple .vue windows on screen to copy/paste from one to another, or "referencing" of layers from other .vue secenes, or detacheable windows and buttonpalettes, displacement mapping...)

but I really would prefer, to have the existing features improved and stable, first of all.
Coherent coordinate systems, refreshing the active view window first, independent focussing on selected obj, non-jumping window, clean handing-over or shutdown of application, cows optimized for different speeds in farm, no memory problems on long runs, terrain editor reviewed, get out the grain from renders, Mac Vue-icons working as they should... That kind of worries.
Look at this forum, pick some.
I'm not sure to up$grade to a n 6 before, or instead of.