OpenMW is similar to OpenXcom, an open source engine that uses the original art assets without modification. 'Porting to UE4' would almost certainly involve the painstaking recreation of every art asset, given the low res/low detail nature of Neocron's graphics. Beyond that, what would it gain to have the exact same art assets in a different engine? 3? 4? 5? years work to end up not really any further than we are now?

I was actually incorrect, Morroblivion finally reached mostly complete status last year - after a solid 9 years work