Ashley, the tool doesn't actually wrap it in an iframe, instead it just adds the canvas element wherever WordPress detects occurrences of the shortcode. It also asks for the 'c2runtime.js' code and makes adjustments for the image and media urls. From there, you just copy/paste the adjusted code into a new .js file and include that in the plugin folder.
mammoth, Velojet, essentially that's what this particular tool does. It outputs a plugin. You just follow the instructions and you'll have your own plugin at the very end. It's just a matter of copy/paste.
This can definitely be much better done as an exporter for Construct 2 though. Construct 2 could very easily export a plugin, the same way this tool outputs a plugin. The only complication really, is with other than static height/width, full-screen apps, in other words.
As for a WordPress plugin that lets you upload your games, I think that could be done and I've considered that as well. It'd basically do what this tool does, but letting you upload the files, then it handles the slight conversion process internally, providing you with a shortcode on a per-upload basis. The upload process for this all is a bit of a beast though.
DrNickTo, I've worked extensively with WordPress so I'm much more comfortable with integration with it. And I'm sorry to say, I really hate Joomla myself, I just think its interface is incredibly bulky and tough to work with. I very much love Drupal though and would love to tackle that integration. Perhaps someone else might be willing to delve into Joomla integration.