Hi,
Improving this delay is probably possible, but you probably don't want to do the necessary changes.
The delay comes either:
- from the emails being sent (so you could disable the email sending during the order creation, or use a faster email sending service, or remove attachments if you have attachments in the emails)
- from a plugin calling a third party service, like a shipping carrier, a payment gateway, analytics, etc.
or a combination of these.
Without these, creating an order take only a fraction of a second.
Regarding your question about adding a message, that's a good idea, but it's not easy to do. It will require some core changes in HikaShop. Now, I think it's a good idea, so we'll be including this in the next version. So I would recommend just updating when we release it.