Having the flexibility to change the appearance of the Issue Collector form would be a nice feature.

Maybe there can be an option to add a custom stylesheet to customize the form style (a simple way to integrate a .css-file) in order to be able to have a full responsive popup for mobile compatibility especially.

in particular this css code, which defined some fields size inside the popup of the collector :

form.aui .long-field {
    max-width: 500px;
}

overriding the popup collector size can be done now using :

.atlwdg-popup {
    height: 90% !important;
    width: 75% !important;
}