>>213742072
The Galaxy class was meant to be a long term city ship for missions that could take many years beyond the borders of the Federation. Designed to provide for all the needs of the crew including the ability to bring their families. The crew could pornteially be gone for 5 to 10 years far beyond the borders of the Federation.
In addition, it was also designed to potentially be a Colony ship to help create colonies on distant planets. The ship would be loaded with colonists and stuffed to brim with supplies and building materials. The Galaxy would drop them off on a far away planet and then come back. Potentially spending years doing it.
All the combat problems you mentioned were fixed during the Dominion war. The Galaxy received a refit for war and became a powerhouse.