#1 Support for Woocommerce stars when posting a review/comment. http://wordpress.org/support/topic/plugin-wp-ajaxify-comments-conflict-with-woocommerce?replies=1 at #2
#2 Element Blocking for #respond with opacity when posting a comment to show the user that something is happening.
#3 fadein effect for posted comment or another effect
#4 Notification like "Growl (the easy way)" from blockUI demo page for succes and with and X (delete mark) instead of check mark if error. And if is loading then have an ajax-loading.gif. (I think this could be provided via css.)
#2 and #3 are meant to better inform the commentator so that he would not post his comment again.
I really like the plugin because of the customisation options and I always wanted a WORKING plugin (like wp ajaxify comments is). there are some ajax comment posting plugins out there but they don't really work.
Now I'm not using it because it has the problems I mentioned.