I was just trying to be helpful, offering approaches that you can already do now, since it may be some time before we could consider whether, and if so how, to implement your suggestions which are now logged on our wishlist.
BTW, the link provided in a thank-you email just leads to the thank-you page we generate for that transaction, where we present the actual download link -- i.e., the buyer doesn't start the download directly from their thank-you email.
The [%download_link%] in product-based thank-you emails would lead to a thank-you/download page for just that product alone, whereas the [%thankyou_link%] that you can put in either product-based or the common thank-you email would lead to a consolidated thank-you page for all items in the buyer's order, which is the same page they would reach after completing checkout, such as this example:
https://www.e-junkie.com/d/?t=jg-l5rooge0092d567&c=fup
While the Common Thank-you Email template cannot use item-specific variables because it is not associated with any particular product, you could still format that template in a suitable manner using only common, order-specific template variables, e.g.:
Dear [%first_name%],
Thank you for your order with [%business_name%]. You can download your purchase from this link:
[%thankyou_link%]
We do already have a default message format for digital goods, so if you don't Enable Templated Email for a product, the default message we already send would follow this format:
Dear [%first_name%],
You can download [%item_name%] at
[%download_link%]
If you add an Email Message for the product (still without Enabling Templated Email), that message would simply be added below the default shown above. Enabling Templated Email would completely replace our default message and allow you to define the entire message from start to finish.