My two cents here. I would like to suggest that the “Translation” box on “Colaborate” section of main site points to a fixed post on “Translations” category here in this forum. This post would explain how to proceed with translations. For example, with language topics with people organizing their work there.
In the actual flow, when we want to contribute, we are redirected to Transifex. There, if any of the team coordinators aren’t active anymore, the strings aren’t reviewed. And someone (in this case, @keunes ) needs to monitor all teams (and Transifex messages) to see if they’re working. If we transfer the organization to here, we would have more eyes on it (and I’m already offering to help with Brazilian Portuguese translations). 
What do you think? (oh, and, since I’m talking about message on Transifex, @keunes please take a look on the one I sent you there). 
About Weblate, I do like it too, particularly some of it’s tools: easily view of other language translations; “neighbors” strings (good to available context in some cases) and a lot of sorting options. But I’m speaking as a translator. Don’t know if developer’s tools/integration are worst.