Any regular reader of Future of Trek
forum will know I've been a big supporter of CGI animation.
A CGI show also has the advantage that it's fairly easy to display really exotic and non-humanoid aliens of many different shapes and sizes.
this is key to a live-action series budget as the makeup/costumes are costly and time consuming.
Although the art department on a Trek movie has the largest number of people building those sets. In CG one person can build a CG model of a location, another person does the lighting, another person the atmospheric effects. Even if you triple this it is minimal compared to live-action. for making a set/location see The Making of Tython in Knights of the Old Republic [5 minute video]
[see at 3:38 specifically]
I've posted these 4 videos before but here they all are in one place.
3 videos show what is possible with a CG animated series with characters, story, camera moves, slow-motion, costumes, alien characters's head design, lighting, action, effects.
Star Wars: The Old Republic cinematic trailer
Resident Evil: Degeneration Red Band (Movie Trailer)
Star Wars: The Force Unleashed (2:12 trailer)
(after 30 second ad WMV or QT
A Trek CGI series has this potential too. And it could go as dark in tone as you want especially for an extended edition director's cut on Blu-ray/DVD that wouldn't be suitable for broadcast TV's TV Parental Guidelines system's TV-PG and TV-14 ratings. Not just in violence but in content
like the BBC not showing episodes of TNG