I would love to see a parameter similar to $wgSimpleBatchUploadMaxFilesPerBatch but for a specific instance of {{#batchupload:}} (e.g. "{{#batchupload:...|limit=5}}"). I know the extension is called SimpleBATCHUpload, but it would help for instances where we only expect a single file but still want the other (great) features of this extension like not having to name files, drag drop, no form to fill, template insertion, etc.
Topic on Extension talk:SimpleBatchUpload
Not a bad idea. Best place to raise this (and make sure it is not forgotten) is at https://github.com/ProfessionalWiki/SimpleBatchUpload/issues Requires an account, though. (Best way to get it implemented is to raise a Pull Request, obviously. ;) )