"When a single Borg ship can wipe out an entire Federation fleet , I would expect the Federation come up with a Battleship or ships of capable of delivering devastating firepower and with multiple shield generators for defense."

They did, the Defiant.

The Defiant was a Federation warship designed to stop the Borg. The Defiant made it's first appearance in the DS9 episode "The Search." In this episode the Defiant was sent on a mission to find the Dominion. The Defiant was equipped with pulse phaser arrays, quantum torpedos, ablative hull armor, multiple shield generators,a large warp core, and a Romulan cloaking device. The Defiant was highly maneuverable with a top speed of warp 9.987 faster then ever shown in it's time not including"Threshold"(Voyager's worst episode and a disgrace to Trek and science.) The ship proved effective against fighting off the dominion and in First Contact the movie not the series the Defiant was shown fighting the Borg under the command of Worf. The Defiant did not deal much damage to the Borg cube but withstood a lot of fire from the Borg cube hence Riker's line, "Tough little ship." While built to fight the Borg. It was technically a heavily armed escort because the Federation did not believe. When Sisko presented the Defiant to his senior staff O'Brien mentions that the Federation didn't believe in warships.

And then there's the U.S.S. Prometheus and it's class from the Voyager episode, "Messenge In A Bottle." The Prometheus was equipped with multiphasic regenerative shielding, ablative armor, multi-vector assault mode, 18 Type XII Phaser arrays, and 5 Pulse fire quantum torpedo tubes + 290 torpedos. Also the Prometheus could spilt in three and attacking from all angles with Multi-vector assault mode.

"When a single Borg ship can wipe out an entire Federation fleet , I would expect the Federation come up with a Battleship or Ship-Of-The-Line capable of delivering devastating firepower and with multiple shield generators for defense."

They did, the Defiant.

The Defiant was a Federation warship designed to stop the Borg. The Defiant made it's first appearance in the DS9 episode "The Search." In this episode the Defiant was sent on a mission to find the Dominion. The Defiant was equipped with pulse phaser arrays, quantum torpedos, ablative hull armor, multiple shield generators,a large warp core, and a Romulan cloaking device. The Defiant was highly maneuverable with a top speed of warp 9.987 faster then ever shown in it's time not including"Threshold"(Voyager's worst episode and a disgrace to Trek and science.) The ship proved effective against fighting off the Dominion and in First Contact the movie not the episode the Defiant was shown fighting the Borg under the command of Worf. The Defiant did not deal much damage to the Borg cube but withstood a lot of fire from the Borg cube hence Riker's line, "Tough little ship." While built to fight the Borg. It was technically a heavily armed escort because the Federation did not believe in warships. When Sisko presented the Defiant to his senior staff O'Brien mentioned that the Federation didn't believe in warships.

And then there's the U.S.S. Prometheus and it's class from the Voyager episode, "Messenge In A Bottle." The Prometheus was equipped with multiphasic regenerative shielding, ablative armor, multi-vector assault mode, 18 Type XII Phaser arrays, and 5 Pulse fire quantum torpedo tubes + 290 torpedos. Also the Prometheus could spilt in three and attack from all angles with Multi-vector assault mode.