Element ( https://element.io/ - a client based on the Matrix protocol) is really pretty cool for instant messages. It also features group calls and has a mobile app that is actually good. It is end-to-end encrypted and the management of the keys can be a challenge for non-tech users, but apart for that, it is really super cool.
If you want to go even fancier, you have WorkAdventure ( https://workadventu.re/ ). It allows you to build virtual offices in a 2D world. It comes with really easy to join video chats, and you can actually put screen-shares in "real" full-screen. It is also compatible with the Matrix protocol so you can send and receive messages from / to Element or any other Matrix client.
Anyway, in a true open-source fashion, you want to have a protocol that is independent from the app itself so that you can have many interoperable clients. The Matrix protocol is just this for instant messaging.
Disclaimer, I work at WorkAdventure
Actually, there might be an easy to use solution! It is called "Self journal of science" and is available here: http://www.sjscience.org/artic...
Think about "Github, but for scientfic papers!"
It features the possibility for any scientist to publish a paper (in Latex because this is what scientists use). The document can be viewed online and each paragraph can be discussed online, using a revision system where pears can review your article (think about a start system on steroids, for scientists).
The project was started by Michael Bon, a researcher who was fed up with the way scientific papers work today.
Disclaimer: I know the developers who work on this project. It is still in development but is already usable. They definitively need some help to spread the word, and more than anything, I know they need papers published on the website. If you happen to know scientists who might be interested, please let them know the "Self Journal of Science" exists! These guys are really trying to make things change and they need your help!
Indeed, using Drupal can turn into module hell. However, we are not only using Drupal for the sole benefit of being able to quick-start a website.
Take a look at this site: Butterflive: live chat and real-time tracking
The front-office part is done with Drupal and the backoffice in Drupal + Mouf. Why did we do it this way?
Well the front-office is very efficient because we have a bunch of static pages to edit. I am a developer, but my colleagues are not. They are pretty happy to use Drupal to edit the static pages of the site. When it comes the back-office part (when you subscribe on the website), everything is coded using Mouf, in a nice object-oriented MCV way. I could have used a framework like Symfony for the back-office, however, I would have had to make a template for Drupal AND Symfony, I would have had to configure Google Analytics for Drupal AND Symfony, and so on...
So in my opinion, Drupal is a valid choice as a platform if you need to develop an application that comes with a lot of static content. Of course, if your application has no "front-office" part, you are better using a "pure" framework.
Now, in my opinion, the real problem with Drupal is that it does not rely on the MVC pattern, and most developers are used to that. Also, it is not object-oriented!
At my place, we have developed an MVC framework that we can plug to Drupal. This way, we get the benefit of Drupal and all its modules, and when it comes to pure PHP development, we have a nice MVC framework instead of those bloody Drupal hooks. If you want to have a look:
It is released as open-source, it is functional, but documentation is not complete yet so I would not recommend using it until we finish the documentation (probably in January).
If you steal from one author it's plagiarism; if you steal from many it's research. -- Wilson Mizner