I feel like 'manhwa/webtoons' can get its own category since webtoons are quite different from manga, (as in the manga magazines) and should gets its own category.

Just my own suggestion; but as a avid webtoon reader, I would greatly appreciate one.

Why?
You are able to search for only manhwa in the Advance search by Genre Page (scroll down to Type, and select "show only Manhwa")

Plus there's already a webcomic tag ...

Sidenote next time you have a suggestion for a tag, you could just post it in the Categories(Tags) Bug Thread , It's for suggestions, bugs, questions (mostly like these should merge etc.)
Wait actually I think you should post it there instead ...

Yes yes, I know I make longwinded comments, but that's just me >.<
I should proof read my comments more, but I won't...
So keep in mind I'm filled with typos

Check out FAQ and Forum Rules if you haven't yet.
For errors linking in threads