I understand that gut feeling. I've worked with many such systems. iommi is not like that though, because we HATE systems that have a nice two line demo but then immediately falls apart.

We consider any failure to scale up customization a high priority bug.

How do we handle this in practice? Nice defaults, easy to do deep customization with zero boilerplate, AND escape hatches of various forms. So if you need to just render your own template for an entire table row of form input field or whatever, you can do that. Always.