I’ve suggested a similar idea before. My idea is that the Federation has lost a major war. It hasn’t fallen apart, but Starfleet has been decimated, and as a consequence of the peace treaty, they aren’t allowed to have anything more formidable than a frigate. (Basically, they get the same deal that Germany got after World War 1.) Most of the characters that we know from previous series are dead. Picard, Geordi, and Dr. Crusher died when the Enterprise-E was destroyed. Worf, Dax, and Dr. Bashir died when the Reliant was destroyed. Deep Space 9 is back in Cardassian hands. Tuvok and Harry Kim died when Voyager was destroyed.
Admiral Janeway is the new president of the Federation, appointed with approval of the conquering powers. She’s widely viewed as a sellout and is hated by most people.
Riker, who was commanding the Titan, survived the war, but his ship was scuttled per the terms of the treaty. He’s currently commanding the Enterprise-F, a heavy frigate that’s roughly the same size as Voyager was. It’s the toughest ship the Federation has, but a Klingon or Romulan Battlecruiser could beat their asses easily.
O’Brien, who last time I checked was teaching at Starfleet Academy, has been pressed back into active duty. His family was killed when San Francisco was destroyed during the war. Naturally, he’s quite bitter about what’s happened to him. He’s also secretly jealous of Riker, whose wife and kids are alive and well on Betazed. (There will be no children on the Enterprise-F! This is a warship, dammit! Troi and the kids will be seen primarily in transmissions from home, and will only be present in person on rare occasions.)
The tone of the series will be different from previous series. The Federation is not the big dog on the block anymore, and it must tread carefully around several larger powers. (Klingons, Romulans, Ferengi, etc.) There will be parallels to the current situation in Iraq. There will be insurgents (lead by Chakotay, B’lanna Torres, and maybe Tom Paris) who commit acts of terrorism to gain influence and attempt to establish themselves as a power in the new Federation. The government is corrupt and inefficient. With supply lines disrupted, poverty and hardship are widespread. (Replicators need raw materials to make stuff with, and the Federation uses huge amounts of energy.) Mostly, it is the colonies and other lesser settlements that suffer, while the leaders make sure that the core worlds are adequately supplied. This glaring disparity helps fuel support for the insurgency. The supply disruptions also mean that piracy has become a big problem, with raiders of various sorts robbing supply ships to either send the cargo back to their planet, or sell it on the black market.
The Enterprise-F will spend much of its time as a sort of galactic police ship, upholding law and order as best it can. There will also be political intrigue, both from the Federation government and from the various foreign powers. And of course, there will be the tradtional Mysterious Anomalies[sup]TM[/sup] that seem to lurk around every corner in Trek.
Time travel will be used sparingly, if at all. Badly written time travel stories really annoy me. Also, Q will have no more than one epsisode, if that. I hate Q.