Can't search for contacts that signed up for specific shifts (time start) - useful for email reminders

Currently, CiviVolunteer an Activity Record of type VOLUNTEER recording the volunteer opportunity sign up with Date and Time of a particular shift with the name of the Volunteer PRoject in the SUBJECT.

It's a major need and missing piece in the volunteer feature to not be able to at the very least search and create a smart group of people who signed up for particular shifts - this allows user to then use the smart groups to use the MAILING feature and other features of Civi.
Currently, you can't search the TIME field in Activity records - so you can search for particular shifts during a day.

Would it be feasible to expose the TIME in Activities for searching or BETTER YET expose both the VOLUNTEER ROLE and the TIME of the shift start from CiviVolunteer for searching activities? I have a group now (and more groups are wanting this) who would need this, otherwise, it's manual process and very difficult when you have a very large number of volunteers and many shifts on multiple days.