I have the same opinion as your first paragraph, but I don't want to spend weeks or months vibe-coding basic features which come built into almost every other agent.
Yeah maybe Claude/OpenCode/KiloCode/Hermes/whatever are not as minimal as Pi but they also work right now.
You don't actually need those features. Initially I began using Pi thinking I would customize the hell out of it. I've installed one extension for guardrails and that's about it. I've been able to do everything I did before just with vanilla pi.
We probably differ a lot in what we consider "basic". Are subagents basic? I found them only useful in very few situations. Is LSP support basic? There are mixed results on whether it helps or hurts. Are multiple choice asking tools basic? I found that they add extra unnecessary ceremony, eat extra context, and I almost never answer with one of the choices exactly.
And if you try vanilla Pi, you will also find out that it works right now.