I love Jerry Goldsmith's oeuvre, but no way would I swap out any of the film scores from the other composers. Horner's work is simply brilliant, Leonard Rosenman's score for IV is hugely under-rated, it really works for that movie - and I adore Cliff Eidelman's work on VI, its very subtle and emotional.
The weakest scores for me are 'Generations', which has some nice work, but seems to be bound by the stupid rule not to be too dramatic, that TNG' producers insistent on having. Sadly, I find Goldsmith's work on Insurrection and Nemesis to be kind of weak by his incredible standards. Especially for Insurrection, the action sequences seem to re-use bits from US Marshalls that he also scored.