Re: The changes in the Enterprise-D bridge in Generations...
It was just more of a movie feel.
But for an in universe explanation check out the book 'Rogue Saucer' which took place between season 7 and the movie. The Bridge is severely damaged in a Maquis attack and needs to be refitted. While they wait for that they test out a new Saucer for the ship which can land and take off planets and has extra weapons etc. The Maquis steal this and eventually it crashes too with Riker on board. Very fun novel.
"It's not that you can see the strings, it's that 40 years later you're still looking at them." - Steven Moffat
"This movie was big. Imagine how big it could have been with me in it?" William Shatner