I would like to request the Disqus commenting integration. It's free, easy to use, and anyone can login using multiple, existing accounts via Facebook, Google, etc...
We're currently working on our own commenting system directly in HikaShop. It should be available in one or two months.
I don't see us developing an integration with disqus any time soon. However, we welcome any initiative on that end so we will gladly help anyone developing such solution.