I imagine they will go ahead and future proof it by doing the digital masters in 4k resolution.
To do visual effects for a Blu-ray release and future syndication in HD would happen in 1080p not 4K. Only tentpole feature films get a 4K pipeline due to the additional rendering needed and storage. Most feature films are still mastered at 2K. Sure I'd love to see Trek at 4K but 1980s TV series Trek is just not going to happen. Be realistic.
Well... Paramount has already been burnt once by not "future proofing" Star Trek: The Motion Picture
Directors Edition, rendering those effects at 480p.
I imagine 4k resolution will be the home video standard by about 2030. And we'll all be sitting here taking our Geritol, bitching that Paramount only did 1080p masters back in 2012.