The plugin documentation/architecture is a bit gnarly (at least from what I remember). That being said, I feel like most WordPress plugins are awful.
I've sometimes wondered if I could make a better version of X plugin, but I fear I'm missing something - like providing customer support or covering every version of WP.
The customer support and testing are key challenges. You have to be ready to help people with things that aren't even your fault if you don't want your rating on the marketplace(s) to go to shit. Plus you'll need to do lots of sales/ads/marketing to get your zero-ratings zero-downloads plugin off the ground, no matter how good it is. Writing a decent and useful plugin is helpful (almost wrote "necessary", but it's actually not—at least the "decent" part) but isn't sufficient to have a successful plugin.
The plugins are both awful and brilliant at the same time. Well, maybe not so much today. But back before I knew I what I was doing, back before Ruby On Rails really took off, it was pretty awesome to have a Wordpress blog, install a plugin, and suddenly you've got a fully fledged forum section on your site.
Of course the architecture and the mode of installation for those plugins used to be horrendous and fraught with so many problems.
You could look into making single purpose blocks. Then you can get listed in the block inserter upon search an site owners an install your block right from there. Some plugin developers made great inroads in active installs with this more friction less process. Once your block/plugin is installed you can provide links in the sidebar to more expansive plugins or premium versions.
The plugin documentation/architecture is a bit gnarly (at least from what I remember). That being said, I feel like most WordPress plugins are awful.
I've sometimes wondered if I could make a better version of X plugin, but I fear I'm missing something - like providing customer support or covering every version of WP.