The "original design" was the UserVoice support system, a fact conveniently missing from the article, which leaves us to speculating as to why they would have moved away from that platform in the first place...
The logic behind the redesign is not a mystery and was mentioned in the article. Here I can elaborate it:
1. To add several new features, UserVoice wasn't flexible enough to provide
2. To automate a few administrative tasks (tracking requests, updating, uploading) - thus no connect the system with our website backend more tightly
3. To cover all these changes in a modern, simplified version of the design.