As described on /hc/en-us/community/posts/360023747733-Custom-fields-in-Blueprints- there is a distinct need to copy the enabled custom fields from a blueprint when using that blueprint functionality. Moreover, allowing users to add custom fields to blueprints gives them the impression that these custom fields will be created when they create the project, which is just not the case. This manual work takes up a lot of time and is something that your competitors offer. This should be a no brainer.
