When trying to ping 3 different projects on a property proposal (about copyright), I discovered that it was impossible, because 2 of those 3 projects have over 50 participants (Books and sum of all paintings).
This is specifically problematic because it concerns succesfull projects, because most participants will never be conscious of this limit, and the notifications will never be done, while the message "project participants notified" is displayed, thus leading to very bad dialog on big projects and it is also very difficult to notify everybody individually.
It would be nice if the upper limit of 50 was removed when ping is made using the "ping project" template, especially when the user adding it is member of the project. This limit makes this template useless precisely where it would be the most useful.
see the discussion on Project chat : https://www.wikidata.org/wiki/Wikidata:Project_chat#impossibility_to_ping_succesful_projects_?