Easy to use.
Linked articles are really useful.
When I copy and paste text, KO adds spans with formatting info. I want to be able to copy and paste without any formatting (CTRL-SHIFT-v).
Synonym library doesn't allow spaces, so I can only add single words. I want to be able to add multi-word phrases (for example: end user).
Ability to use related article feature without autogenerated related articles (I want to choose which articles are in the related articles category).
Ability to convert categories to articles.
Search could be a lot better.
Better wiziwig - easier access to source/output comparison.
Need better versioning options for categories.
Ability to bulk edit.
Problems with previous tool:
It lacked support for many standard product documentation authoring and user features.
It lacked support for implementing modern web features.
The search sucked.
Benefits of KO:
It is a help-authoring tool, designed for technical writers, which means it has:
A simple editor as well as access to topic source
Standard editor/writer/review workflow for content
Topic versioning: multiple versions of a topic can be in draft form.
Content reuse: dynamic templates, snippets to keep all content in-sync.
Semantic styling: tagging of content bits for easy restyling.
It is a modern web tool, which means out-of-the-box we get:
Cloud hosting for the tool and docs
Instant publish/build/re-index of the entire doc site
SEO tools (refine categories, related articles, recommend pages, search phrases, synonyms, exclude-from-search, a Google Custom Search option)
Responsive design (try it on your mobile device!)
Standard reports, Google Analytics option
User comments, ratings, search suggestions, other self-help stuff
Contact form with search integration
Link by topic ID, not topic title (to prevent broken links)
Easy access to the power of web programming (e.g., REST APIs, site-wide and topic styling and scripting)