What's wrong with building modern ships to replace attrition, rather than just fixing out-of-date ones? It seems pretty counter-intuitive, and to restrict the federation to a weaker position than necessary is just as much of a lazy writer's fiat as to fanwank a huge BFG ship.
"You fought with Captain Reynolds in the war?"
"I fought with a lot of people in the war."
"And your husband?"
"I fight with him sometimes, too."