Feel free to answer the question in the title as generally as I posed it, I offer some more details and specifics below.
Currently I develop and maintain a somewhat legacy business app (ASP/SQL) that is highly customizable allowing for moderate to full customization on: custom fields, forms, views, reports, actions, events, workflows, etc. This customization is necessary in the domain we develop for and has allowed us to build a niche.
I have been reading up on the inner-platform effect and ways of implementing high level user defined customization and have concluded that we do suffer from many of the inner-platform effect problems because essentially we have created a high level abstraction on top of the SQL. The organization of custom fields is implemented in a similar way to the approach found here
http://blog.springsource.com/arjen/archives/2008/01/24/storing-custom-fields-in-the-database/
We use something similar to the meta database method described in that article. All customization is built around this approach and in many ways we suffer from database on top of a database.
The end result is something that looks fantastic on paper yet the more features are added and custom coding is done for clients the more of a mess everything becomes. It seems that the more I read the more I realize this is somewhat of an anti-pattern. It also seems that the more I try to read the more I find so little has been written on the topic. Anyways, I am trying to learn modern approaches to this problem and trying to find more discussion/articles on the topic. Are Database systems such as CouchDB relevant to this type of application?
My question is clearly pretty general. It seems like there is a lot against this kind of application in favor of just "knowing and defining your domain better". Are there any good/better ways to implement this kind of application? I'm not looking for black and white answers, and any further readings on the subject would be fantastic. Thanks for any help.