The developer of Dash is very receptive to feedback (in fact I think this change was called out as something that he was interested in hearing opinions on).
First one took a year before I got a reply (after reminding him), and only partly answered the request.
The second one I'm still waiting for a reply.
I would love for Dash 5 to fix these issues still, and I would upgrade in a heartbeat, but as it stands, I'm stuck with Dash 4.
The issues are:
1. Dash 4's sidebar shows significantly more hits when searching, making it a lot easier to find what you were looking for, compared to the "omnibar" of Dash 5:
https://i.imgur.com/smuNFws.png vs https://i.imgur.com/SeTShSL.png
2. Dash 4 shows/loads the currently selected search immediately, requiring no extra step. Dash 5 requires the user to press enter to confirm the search. This is especially frustrating when triggering a search from an editor
edit: where did he indicate he was looking for feedback on these features?
I thought it was in the release notes for v5, but I can't find them at this point to verify. I suppose I may be misremembering.