Frankly, I do not have any plans to modify the plugin as my understanding is it isn’t needed.
The action of consent is given by the action of entering the name and e-mail address into a form specifically for the purpose of a mailing list. Any required text can already be added in the widget text. A checkbox to say “yes, I’m giving you my e-mail address and name” when all the form is doing is asking for your e-mail address and name for a subscription isn’t in line with my understanding of the GDPR.
A checkbox opt-in is required on, say, an account registration form or some other time you’re collecting personal information where it isn’t clear that you’re going to that information for the purpose of e-mail marketing.
If your compliance office would like to have a checkbox, you can add within the “Hidden Fields” box a <input type="checkbox" id="subscribecheckbox" name="subscribe" value="newsletter" required="required"><label for="subscribecheckbox">Subscribe to newsletter?</label>