Option to name any step & change column name in expand step

While performing a new step from UI (for ex Merge) there should be an option to Name that step right away as doing it after wards unnecessarily takes time in case of large number of records. Also after merging during column expansion there should be an option to set new names of columns without creating new step. We can do that by modifying "Expand" step itself by changing new column names but that can only be done after Expand step is executed which is time taking in case of large number of records.