I totally understand both sides of this. However these 3rd party plugins we have thanks to this being possible is what makes construct 3 an option for serious projects. Just knowing that if I run into a limitation of C3 I can still probably find help solving it thanks to some 3rd party magic. This have happened multiple times, so without this reassurance I would almost not dare to start a bigger project in C3 to be honest.
I work at a big game studio and we work in Unity as the game engine. Once a project is started, we pretty much lock that development in to that version of Unity.
We also use 3rd party plugins which our current version of Unity supports. And as long as we are fully aware of this risking to break before we start to use the plugin it is up to us to decide if we should use it or not, knowing it might break in the future.
And later down the line we might update Unity for reasons and realize a plugin we used isn't supported anymore.
What do we do then? We fix it, either the plugin itself or replace it with another solution. Sure, it can be a pain, but we knew it could happen and we still made the decision to use it.
What we would never do though, is to blame Unity or any other game engine we used. It is entirely our own fault. I feel like anyone that is experienced enough to install plugins should understand this as long as there was a warning about it.
I mean there are so many things a beginner developer could do wrong in their projects that will turn out to completely break their projects down the line. It is just a matter of learning what risks to take and not take based on project scope.
So I think the easiest and best solution would be to CLEARLY warn users when installing these plugins. You as a user should understand that Construct is not responsible if this plugin breaks in the future.
Just my 2 cents about this discussion.