I think what is going to be a big factor if a new series will happen is how well "Star Trek into Darkness" does in theaters. From the previews, critic reviews, and from what has leaked online, I would not be surprised in exceeds $300 million. Home video sales are usually considered irrelevant by the studio.
Now about Greenscreen / Virtual sets vs Real Sets. They probably will build real sets for the ship because that will just be a one time investment. Paramount still has a lot of set pieces from prior Star Trek shows in storage that can be re-assembled and re-dressed to look like a brand new series. That would be cheaper and faster for the scenes that take place on the ship. Plus its more believable when you see the actors touching the controls. When an Away-Team beams down to a planet or another ship, most likely Green/Blue Screen be used or be combined with real sets / on location shooting. All depending on the story.
Its a no brainer that all the external space ship shots be CGI unless they bring in an old fashion minded executive producer that wants to use models. However, even some of the modern Science Fiction productions use combinations of CGI, models, real footage of explosions, etc. Sometimes its easier to just go somewhere with a camera and film it.
As for what the Star Trek series needs. All 5 live action shows had a strong Captain at the center of everything. It needs a good, strong, charismatic, actor/actress to make it work. The first officer also has to be at near the level of the Captain, some may argue one of the reasons why Star Trek Voyager falling behind because Chakotay did not live up to Spock, Riker, or Kira.