‘Not installed’ tags on the content manager page is an annoying one and, despite my first ever CTD with it, I must confess I really like WU IV.
Both graphics and performance, for the very first time since initial release, seem to be optimized, ie tree draw distance significantly improved, much less almost no stutters over and around dense PG towns, way higher FPS.
What I, in particular, like is that building archetypes make whole France look as if rendered in PG, as an eye-candy.
Still a long way to go for sure, outstanding areas to be improved, though :
Realistic ATC
Garmin issues
Seasons
Yet better water textures in calm weather
DirectX12 and all of its benefits
whereby, many of the above are actually being worked on by the MS / Asobo team.