Honestly? It won't happen.
The reason I wrote Akeeba Engage was that I wasn't exactly impressed with the performance of the other comment systems for Joomla. I realised that the technical reasons for their bad performance came down to one common root cause: they tried to support every component under the sun. This has some corollaries.
For example, each comment needs to have a double key defining the extension and the item ID that is being commented on. Even if you use the numeric extension ID and create a MySQL combined key (both of which none of the comment extensions do) you have a slow query to get the comments.
Further to that, trying to have a consistent user interface for setting up comments in different component requires making a lot of concessions, from the fact that the content categories / items and comments configuration are disjointed in your backend interface to which options exactly you can implement.
When you put all those things together you realise that no matter what you do to support multiple components you'll end up with something over-engineered and slow by definition.
Akeeba Engage goes the opposite way. I started from a clean slate. I set forth a few design principles. It will be fast. It will support nested comments. It will not be hurting your SEO. It will use microdata. It will not have a disjointed interface i.e. comment options will appear into the options of the categories and content items which are being commented on. It will use standard Joomla content plugins to allow Joomla itself to manage the page or component caching (because we have Progressive Caching since 2010 and we'd better not ignore it like everyone else). The combination of these design goals pointed towards a singular direction: I could only support core articles.
I like my comments lean and performant. There is already a saturated market for comment components supporting third extensions other than core content. Trying to make yet another clone of them, sharing the same performance issues, doesn't make sense to me. As a result I am not going to add support for any third party component.
Nicholas K. Dionysopoulos
Lead Developer and Director
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