I’ve been suggesting the ISBN feature for years. I’ve also requested that the “edited book” and “book section” be changed to work the same way that they do in Citavi - that is, you only have to enter the bibliographic information for the entire book once and then each chapter is captured as a “contribution”. These two features would save a lot of time when capturing sources and would minimise the possible chances for capture errors.
From my perspective, it seems that the replies to these suggestions were skeptical of how useful such features could be to the average user.
When I first started using EndNote about 10 years ago, I really liked the way that I could organise my sources and use the software’s features to keep all my info easily accessible. Now, I realise that the developers base their feature set almost exclusively on what’s required for the natural sciences, while still maintaining some functionality for the humanities and social sciences users.
To be entirely honest, when I start my next big research project I don’t know if I’ll even bother to stick with EndNote. I used Citavi in undergrad and I’m seriously considering making the change back come next year.