I’d like this feature too. There are sometimes problems when importing data curated by other organizations that I could fix quickly using a regular expression find and replace. In particular, sometimes the DOI field contains the DOI, the DOI embeded in the dx.doi.org URL, and bizarrely, two copies of the DOI, the second one followed by a period. Neatening these up with a regex would be super helpful, because now I have to hunt and peck through hundreds of entries.