So revisiting omeka-s-themes/papers#11, the issue wasn't that Collecting needed nicer default styles.
Papers needed to generalize its form styles to extend outside the advanced search form. Collecting uses Omeka S's default form markup patterns and leaves it up to the themes on how they handle styling those forms.
That particular example was having conflicting style issues due to the way the theme implemented page-specific body classes.
See https://github.com/omeka-s-themes/papers/issues/11. Mainly make input widths consistent where possible.