OK, read through the GammaMarkets suggestions. Looks to be some good stuff in there, although looks to add NIP-15 type stuff into NIP-99 which makes me wonder why “we” didn’t just update NIP-15 :-)
In summary it looks like using Collections as apposed to Stalls, improved shipping, reviews, NIP-17 vs NIP-04 DMs, and easier to hook in other payment gateways.
What happens to stall info such as description, banners etc.?