Feature request, do not import blank fields for existing records

I have a lot of input forms. People maybe entered on multiple forms with different fields filled out. Example, form one has Name, email, phone. Form 2 has Name, email, phone and interests. Not every field is filled out.
When I import form 2, if the email was already imported in Form one and includes all fields but the phone number is not on the second form, it will blank out the person’s phone number in the master record.
So form one has a record
Shirley, [email protected], 333-1215
Form two has Shirley, [email protected], , writing.
This wipes out the phone number from Shirley’s record.
Can you change your import to NOT overwrite a non blank field with a blank field? It would save my life!!!
Thanks