Here's my take
THE ERA - My personal preferance would be the era between the 23rd century seen in the original films and the early 24 th we heard about in TNG they have always struck me as the most interesting and dramatic era's. You got the feeling that the galaxy was still a mysterious and dangerous place back then not the anodyne sterile place it became in TNG , not that I'm slagging TNG off it was a great show you just felt though that this crew had seen it all before and had catagorised and filed it under been there done that. The late 23 rd/early 24 th century on the other hand was an era that saw old alliance's crumble(the Romulans & Klingons) and the emergence of new ones in the form of a tenuous alliance between the federation and their most implacable foes the Klingons. An alliance that would be tested by Romulan treachery and come through strengthened by the Noble sacrifice of Captain Garret and the crew of the Enterprise -1701 -c early in the 24 th century. A era rich in potential for furture exploration surely. That said I think their unlikely to go in the prequel direction again after ENT which is a shame as there is more potential in exploring Star treks gritty and rich past then it's annodyne future( which save destroying the federation in the next series will only get more utopia like and boring the further they push into the future).
THE CREW - First things first whatever ship they set it on there has to be more aliens in the crew and on the bridge( an Andorian maybe they are founder members after all) as it seems most of the time to be a humans only club. If anything the further into the future they take the next show the more aliens we should see in starfleet uniforms, if as is my humble wish they dare go the prequel route again I think they should set it on the Enterprise C who's ultimate fate though tragic would make a grand standing finish to any series.
THE FORMAT - Twenty six episodes a series is one hell of a punishing schedule why not go the hbo route and do 12 great episodes with an increased budget for each instead, or failing that take a six month Hiatus after the first ten episodes to fasion the next 10 ala RDM's BSG. We'd be more then willing to wait if the qualities good.
THE MUSIC - Too long have we trekkies had to put up with elevator music on our shows which enhanced the onscreen action not one jot. Its high time a proper composer was brought in fulltime and not just to score the opening credits. If the powers that be saw fit to change the format as I've elaborated on above a prospective composer might have enough time with the material (ie the episode Script or dailies from the ep shoot) to craft a moving and gripping score not just for sweeps episodes but for every episode, how great would that be.