The names of the dead would be raised to the plaza from the pool level below, as many relatives have demanded. But thundering waterfalls would still cascade into those pools, at the bottom of two enormous voids marking the place where the twin towers stood. The reconceived World Trade Center memorial and museum, unveiled yesterday after weeks of anxious anticipation, tries to solve security problems, placate disaffected family members and, most of all, reduce the project cost from an estimated $672 million. A budget target of $500 million was set last month by Gov. George E. Pataki and Mayor Michael...