So I don't use stuff like Superpowers either - I think if it were actually that good, it would work it's way into the core product.
But I do mod Claude Code to incorporate gotchas from my specific workflows. For example: Which snowflake instance should you look at, where are the tables in my data warehouse, [Product] doesn't have an API, here's a Skill that uses the Chrome MCP to handle repetitive tasks, here's an agent that should explore the schema, you don't have write-access to this repo. A recent skill I made was to modify our terraform config (after doing it 4 times in the same way) - it requires pulling the ticket from JIRA, knowing how our terraform config works (or at least the bit I'm interested in), and making a pull request in a certain format.
Agents solve a real problem of keeping your main context shorter, and you can also have your main thread on Fable/Opus/Sonnet, but use Haiku for certain tasks in a subagent because you know the dumb AI can figure it out - but you need to think about the tasks in your job.
I've done my fair bit of modding with electric bicycles and 3d printers and in general the lesson I learnt is that a small bit of modding can cause an improvement (e.g. I want a usb charger from my battery), but overmodding breaks things, and either you want ebikes and 3d printers to be your hobby, or your hobby can be fixing your ebike or 3d printer. I think the same applies to claude code or Vim. Incidentally I never modded vim.