A/N - I don't own Star Trek The Next Generation. Please let me know what you think.
The Battle of Wolf 359 was one of the most devastating battles and losses within the Federation's history of interstellar warfare. Despite being an organisation devoted to peace, long experience among all the powers who had come together to form the core of the Federation had learnt the hard way there would always be enemies.
But now the Borg encompassed them all. In the 23rd century, the Klingons had been constantly trying to launch wars of expansion against the Federation, but the Klingons and others like them were in the nursery compared to their Borg. A cybernetic species from the Delta Quadrant, the Borg had become a powerful enemy because they forcibly abducted species and subjected them to a brutal process called assimilation where individuals would become Borg themselves, their brains would then be linked to a central Hive Mind, and their knowledge would become a part of the Collective. At the same time, all individuality would be erased and they would become mindless automatons. And it wasn't just people whom the Borg assimilated, but ships and other pieces of technology and hardware would also become assimilated to allow the Borg to understand it and advance because of it.
The Borg Cube which had attacked the Federation, abducting Captain Jean-Luc Picard of the USS Enterprise was a product of centuries of assimilation, cherry-picking the best bits from so many races and cultures and then integrating them into a formidable killing machine.
As the admirals who had gone to witness the site of Wolf 359, the sight was forever burnt into their memories.
It was a massacre. The fleet Admiral Hanson had formed to protect Earth from the Borg to prevent assimilation of the Federation was completely destroyed, some of the ships were more or less intact, showing terrible damage to their saucers and secondary hulls and their warp nacelles, but there were destroyed hulks with their saucer sections torn in half and the rest of their hulls destroyed, some of them still glowing with fire from whatever remained of the emergency forcefields trying in vain to keep the vacuum of space at bay.
At the sight of the devastation, Starfleet began taking the Borg threat and the Q entity's warnings to heart.
The universe was a deadly place, and the further Starfleet expanded their exploration missions, some of which could last up to a decade, there was the chance they could encounter an enemy as powerful as the Borg or more dangerous than the Klingons or Romulans of the past. With the loss of so many starships, the Fleet was vulnerable. So was the Federation.
The President of the United Federation of Planets met with the commander of Starfleet and they came to an arrangement to prevent such tragedies from ever happening again. Upon learning that Starfleet's adoption of the 'head in the sand' mentality had cost the Federation the time it needed to make prototype weapons which could have saved lives, the President and the Commander of Starfleet formed a division which would ensure it never happened again.
At the same time, Starfleet agreed with the upcoming investigation which was set up to discover precisely what happened and what went wrong with the Battle of Wolf 359, the design of starship, traditional for decades, was just not entirely practical. Warp nacelle pylons were vulnerable and so was the conception of two standard hulls, the primary and the secondary. While their ships could withstand a great deal, against an enemy as powerful and aggressive as the Borg, the ships were easy to defeat.
It was decided to totally redesign the fleet, a decision many of the traditionally minded shipbuilders and admirals disputed but their voices were drowned out by the logic of the arguments, some of which were practically driven by the problems of researching for faster warp field technologies forced radical issues which delayed the design process of a ship. In any case, their voices were further drowned out by the orders to find better alternatives.
Designers and historians looked into history files for old warships and aircraft for inspiration, and they further came across science fiction in the form of 'Mass Effect' and 'Halo' and old television science fiction series like 'Battlestar Galactica', 'Doctor Who', 'Babylon 5', 'Stargate SG1 and Atlantis', for inspiration. They had seen many interesting designs and concepts, but it was eventually decided to rely on simpler, and more compact designs.
They began constructing ships inspired by the form seen in Mass Effect and in UFO, where there would be a delta-shaped craft and saucer-shaped vessels with warp drive inbuilt and boasting an impressive weapons array. The Defiant and Akira class starships were more of traditionally conceived stock, but they were still effective the Akira class featured their nacelles underneath but were heavily armoured and there were phaser cannons near them designed to protect them.
Designs for large fighter carriers and medium warships were considered and ultimately approved. The thought of transforming a fleet of exploration vessels and replacing them with warships did not sit well with many in the Federation, nor with Starfleet. But while the Borg threat seemed to have eased off, the President was determined to ensure the same complacent mistakes were never made ever again. So many lives had been lost, and even more, could have joined them.
However, not was the design of a new class of starship which could join a warp ring to provide the ship with its propulsive power was a key breakthrough.
Inspired by the Star Wars prequel movies of the 21st century, the warp ring represented one of the greatest boons and advances Starfleet had ever had. The ship would join the warp ring after keeping it in a safe place and would rejoin with the ring, and they would once more have the faster-than-light capability. The ship would simply have the power plant for the warp drive, but the warp rings could provide slightly higher warp velocities due to the freer constraints. In the past, designers and warp specialists had always had problems with higher speeds because of how the inertial dampening system was forced to compensate at all times. But with the warp ring technology, the ships would just have to connect the power drives and activate the ring, and only a minimum amount of the stress would affect the ship.
As new and more powerful starships entered service while the warp ring inspired more warp specialists to begin looking into improving their warp technology and looking into alternative forms of Faster-than-Light technology, planets were also fortified to slow the Borg down and to provide an early warning system.
Later, while the Borg threat was less urgent, Starfleet was left reeling when the Dominion War began, but with their advances in weapons and defence technology, they proved more than a match.