Is there a way to add comments without automatically adding curly brackets? For example, i want the files comment to say: [[Category:Some Category]] {{some page}}
Topic on Extension talk:SimpleBatchUpload
Yes, there is, although it's a pretty convoluted system. The way to do this is to make a kind of wrapper template, let's say we call that Template:Plaintext. Then if you use a BatchUpload box like this:
{{#batchupload:subst:plaintext|[[Some Category]] {{some page}}}}
and simply put {{{1|}}}
on the template page, that should just output whatever you entered as the first parameter.
Note that it might also be useful to use the same trick on MediaWiki:Licenses (and possibly change MediaWiki:License accordingly). The template you're substituting can be as complicated as you want. It's also possible to use switch statements in that plaintext
template, for example. As a demonstration of one implementation you can see this template (also see the relevant MediaWiki messages I linked on that wiki).