If they want to re-do some of TOS then they should do a version of the second 5-year mission (per Phase II). That would basically have been the TOS crew, including Dr Chapel and Transporter Chief Rand plus Decker, Ilia, and Xon. Even if they decided not to bring back Decker and Ilia like in the original concept (basically Riker & Troi) they have dipped their toe in the water to expand some of the other alien species like Saurians, Andorians, and Tellarites. They could probably have a few semi-regular characters like Sam in SNW to round out the cast. I would actually like them develop Deltans more so let's include Ilia's twin cousin, Ilooa.