Firstly Im a massive fan of NopCommerce and guys who build it. I hope this is seen as constructive criticism.
To me the nopcommerce offering has 2 main areas it should focus on:
1. Improving the design of nopcommerce.com, the default skin and admin system
2. Basic UI improvements of nopcommerce and the admin site.
1. Improving the design of nopcommerce.com, the default skin and admin system
When I quote for a project to a potential client I have to sell them NopCommerce as an offering. I do this by pointing them to work I have done in it plus the nopCommerce.com site. They compare it directly to products like Magento and WordPress/WooCommerce. If I look at nopcommerce.com and the default skin of both the public site and admin system it bears no comparison whatsoever. Nopcommerces offerings look 10 years behind.
One of my clients recently (who really loves nopcommerce by the way because we built https://www.mulberrybush.co.uk/ for them in it) suggested the admin system must have been built in the 1980s.
These things are VERY important to nopcommerces success because if we as developers cant sell it to clients it wont succeed.
2. Basic UI improvements of nopcommerce and the admin site.
To me there are very basic UI improvements which could be made rather than always focusing on delivering new features. Take one simple example... Im a not logged in customer and I see an out of stock product. I click to be notified. It takes me to the login / register screen with no explanation whatsoever. Assuming I figure out I need to register when I do so Im directed back to the homepage. Have I been subscribed? No. Terrible UX.
The same goes for lots of basic functions in the admin system, and bear in mind many of which will be used repetitively by staff so big time savings can be made. For example I go to page 3 of a product listing and edit a product, when Im done it sends me back to page 1. WTF? Equally Im on a product page and I flick to edit a specific tab. When I click and save it switched me back to the default tab. Again WTF.
There are so many examples of things like this which trust me are very important to clients and will make nopcommerce a significantly better product and one which is much easier to sell to potential clients.
Just my 2p.
I would also be happy to help out on these simple things and suspect a lot of NOP developers would.