Next question: should it be done as if it were still the mid '70s or done with the benefit of forty years of hindsight and improved resources (while still keeping it TOS centric)?
Compromise. Style wise the graphics can be made from a 21st century point of view (color, 3D models, layout, etc...) Content wise keep it TOS specific. Only use information from subsequent series when the information isn't mentioned in TOS (such as a galaxy map, the location of the Romulans in relation to the Klingons, the name of Koloth's ship from Trouble with Tribbles/Trials and Tribbilations
Oh, and include TAS and TMP at least.
That's my suggestion.