This may apply to other types of modules, but the Search module is the one where it is most prevalent to me.
I would like to see the search module interface changed to be easier to work with in environments where there are a lot of custom fields.
Instead of it loading every custom field in the system as part of the Search Criteria and Outputs, have it only load the system fields by default. Then have a place where you can provide an ID of the custom custom forms whose custom fields you want to be included as well. Or you could have a list of checkboxes with the custom forms listed and let them be selected that way. personally, i like the idea of just making me provide the ID rather than having to store that whole list of custom forms in the module.
This could cut down on the size that the module adds to your blueprint because the list of custom forms is inherently always going to be smaller than the list of custom fields in the system. More so if you just make the end user provide an ID rather than giving a list because then you aren't having to store either list in the module.
This would also make using the modules easier. Particularly in environments where you have a lot of custom fields. When configuring these modules right now, you pretty much have to use the Find feature of the browser or something similar to efficiently get to the fields you want to use. If only the fields from the forms you're interested in are displayed, it is much easier to just scroll through them.
It would also help you be aware of what all fields are on the particular form(s) you're working on.