I've been using Retool very seriously over the past few months. It's definitely helpful to iterate on some UI ideas and prototype. Once you want to do anything complicated that involves any sort of logic, it becomes very clunky since you're trying to write JS in a tiny web-based code editor box. Refractors (e.g. changing a variable name or deleting a query) is kind of a nightmare since I can't just search for it's us…
Anyhow — thank you for the feedback! I will send you an email in a few hours too. If you'd be willing to hop on the phone to dive into some of this in more detail, it'd be really appreciated. (I'll probably run a few potential solutions by you and see which ones you like.)