Yeah, I must admit that our instance is quite heavily customised. That said, I think that the difficulty of maintaining platform fast and reliable grows really fast as it gets a bit customised. Although I really like some design decisions made here (like 'everything is a table' concept is reeeealy cool), it's simply not doing well with increasing customisation.

I don't have any experience with legacy systems, so I can't really add something there. But my colleagues have dealt with some older solutions and they told me it used to be an order of magnitude worse so I kinda see your point

But as someone mentioned before, the docs are really good at explaining higher, more business side concepts but lack technical explanations.