1) Italic or bold characters, as well as bullet points in the description: this is not urgent, but it would help to make the text easier to read and emphasise the product's features.
2) Discounts for one or more products: these could be open to everyone for a limited amount of time or be specific for one client, for example a single-use code. Or perhaps a combination of both: a discount code available for everyone that expires on a specific date.
3) Uploading more than one file: this feature would be very useful when offering product bundles. For example, 6 pdf-guides sold with a special offer.
4) Customisable confirmation e-mail & general e-mail flow after purchase: these would help create a deeper connection with our audience and could even include the option to add reviews to each product they purchased.
5) Require a VAT-Number and address by default: in fact, this would be very helpful if applied to all - products, booking types, packages, subscriptions, etc. Right now, I added questions to all booking types (products don't even offer this feature) and marked each one of them as "Required" to solve this issue. However, it would be much easier if the VAT-Number and required address fields would appear by default whenever a client is about to pay, in order to keep the admin quick and up to date.