I think when I die in ~50 years that HN will still be filled with stories ragging on Jira, or whatever it is that eventually replaces it. It's like the pastime that will never end.
To be clear, I think it's great to see open source projects like this, and I think increasing competition is a really wonderful thing. I also totally agree that Jira has lots of room for improvement, with performance probably being the most common gripe. But I always smirk a little to myself when I hear complaints that are solely from a particular point of view (usually an individual developer). Project management tools have an extremely difficult task of needing to fulfill a gargantuan range of requirements for many varied stakeholders (frontline devs, dev managers, product managers, business leads and execs, sometimes end users depending on ticketing functionality, etc.)
Some simple pieces of evidence:
1. For one, just look at the varied list of comments already coming in on this story "does it support multiple issue types or tiered issues?", "Does Plane offer all the pro features for free because we can't afford to pay anything for it?", "Does it support Google login or other identity providers?", "It needs a walkthrough video that must be short, I'm not going to look at a long video", "Is Ctrk+K a good shortcut?", "Can't add an issue on iPad", "Can it autodelete issues after 30 days of no changes?"... Point being, for any project management tool, you're going to basically get feature requests as varied as the number of comments, and I think I see this more frequently with project management tools than almost any other type of software.
2. Think about the legions of Jira competitors that have popped up: Asana, Basecamp, Monday.com, Linear, Rally, YouTrack, ClickUp, Trello (obv. under Atlassian now, but can't count the number of times I've heard "We loved Trello because it was simple and easy to get started, but we eventually outgrew it and needed additional features."), etc. etc. I have yet to ever hear one of those competitors being universally loved. On the contrary, I've seen cases where a competitor is touted as "the next big thing", and then when it gets more popular people talk about how much they hate it (Asana comes to mind in that regard).
In general, I don't think the problem is the tool, I think that most people just don't like to do ticket management, so it's all a case of looking for the "least bad" tool out there.