Re: How would you improve Insurrection?
Go back before they started writing the film and make sure that Stewart and Spiner have absolutely no input. Then go with Piller's idea of serium krellide as the basis for all Federation medical technology.
Make the Ba'ku likable, drop the S'ona and make it a purely Starfleet vs. Starfleet affair.
J.J. Abrams didn't change Star Trek, audience expectations did.